DNS Services

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Community Training Classes & Labs > DNS Services Index

DNS Services

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Lab Environment

_images/site1_site2_remote.png _images/orientation_RDP_to_branchoffice.png _images/orientation_remote_site_DNS_callflow.png _images/orientation_remote_site_HTTP_callflow.png _images/orientation_remote_site_MGMT.png _images/orientation_remote_site_MGMT_connected.png

Class 1 - Intro to GSLB

_images/class1_availability.png
  • Students will configure F5 DNS servers to support GSLB services on a single device in site1.
  • Join an additional F5 DNS server in site2 to the GSLB cluster.
  • An Internal group of DNS servers is authoritative for the zone example.com and contains a static A record for “www.example.com”, which resolves to 203.0.113.9.
  • Students will add glue records and delegate gslb.example.com to the F5 GSLB DNS servers.
  • Convert the A record “www.example.com” to be a CNAME record pointing to www.gslb.example.com.

At the end of the lab students will have configured F5 GSLB DNS servers to alternately resolve www.example.com to 203.0.113.9 and 198.51.100.41

Settings

A site specific sync group name will be created, and synchronization will be enabled.

Navigate to: DNS ›› Settings : GSLB : General

Configure the global settings for GSLB according to the following table:

Setting Value
Synchronize checked
Group Name EXAMPLE_group
Synchronize DNS Zone Files checked
_images/gtm_global_settings.png

https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/dns/settings/gslb/properties_general.jsp

TMSH

tmsh modify gtm global-settings general synchronization yes synchronization-group-name EXAMPLE_group synchronize-zone-files yes

https://support.f5.com/csp/article/K13734

https://support.f5.com/kb/en-us/products/big-ip-dns/manuals/product/bigip-dns-implementations-12-0-0/4.html

Listeners

A listener object is an specialized virtual server that is configured to respond to DNS queries.

We will be creating both TCP and UDP based listeners.

_images/class1_listeners.png

Logging

Configure DNS query and response logging. Create a “Log Publisher”, and a “Logging Profile”

Note

It is required to complete the following task on both gtm1.site1 and gtm1.site2

  1. Navigate to: System ›› Logs : Configuration : Log Publishers

    _images/system_log_publisher_flyout.png

    Create a local syslog publisher according to the table below:

    Setting Value
    Name local-syslog-publisher
    Destinations local-syslog
    _images/sys_syslog_publisher_details.png

    https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/system/log/create_publisher.jsp

    https://gtm1.site2.example.com/tmui/Control/jspmap/tmui/system/log/create_publisher.jsp

    On both gtm1.site1 and gtm1.site run the following command:

    TMSH

    tmsh create sys log-config publisher local-syslog-publisher { destinations { local-syslog { } } }

  2. Navigate to: DNS > Delivery > Profiles > Other > DNS Logging: Create

    _images/dns_logging_profile_flyout.png

    Create a new DNS logging profile as shown in the table below.

    Setting Value
    Name example_dns_logging_profile
    Log Publisher local-syslog-publisher
    Log Responses enabled
    Include Query ID enabled
    _images/dns_logging_profile_create.png

    https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/dns/profile/dns_log/create.jsp

    https://gtm1.site2.example.com/tmui/Control/jspmap/tmui/dns/profile/dns_log/create.jsp

    TMSH command for both gtm1.site1 and gtm1.site2:

    TMSH

    tmsh create ltm profile dns-logging example_dns_logging_profile enable-response-logging yes include-query-id yes log-publisher local-syslog-publisher

https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/bigip-external-monitoring-implementations-12-0-0/5.html

DNS Profile

A DNS profile controls the way a listener processes a query.

Note

It is required to complete the following task on both gtm1.site1 and gtm1.site2

Navigate to: DNS > Delivery > Profiles > DNS: Create

_images/dns_profile_flyout.png

Create a new DNS profile as shown in the following table.

Setting Value
Name example.com_dns_profile
Unhandled Query Action Drop
Use BIND Server on Big-IP Disabled
Logging Enabled
Logging Profile example_dns_logging_profile
AVR statistics Sample Rate Enabled, 1/1 queries sampled
_images/dns_profile_settings.png

https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/dns/profile/dns/create.jsp

https://gtm1.site2.example.com/tmui/Control/jspmap/tmui/dns/profile/dns/create.jsp

TMSH command for both gtm1.site1 and gtm1.site2:

TMSH

tmsh create ltm profile dns example.com_dns_profile use-local-bind no unhandled-query-action drop log-profile example_dns_logging_profile enable-logging yes avr-dnsstat-sample-rate 1

https://support.f5.com/csp/article/K14510

UDP Profile

A UDP profile is associated with a listener.

Note

It is required to complete the following task on both gtm1.site1 and gtm1.site2

Navigate to: DNS ›› Delivery : Profiles : Protocol : UDP

_images/udp-dns_profile_flyout.png

Create a new UDP profile as shown in the following table:

Setting Value
Name example.com_udp-dns_profile
Parent Profile udp_gtm_dns
_images/udp-dns_profile.png

https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/dns/profile/udp/create.jsp

https://gtm1.site2.example.com/tmui/Control/jspmap/tmui/dns/profile/udp/create.jsp

TMSH command for both gtm1.site1 and gtm1.site2:

TMSH

tmsh create ltm profile udp example.com_udp-dns_profile defaults-from udp_gtm_dns

TCP Profile

A TCP profile is associated with a listener.

Note

It is required to complete the following task on both gtm1.site1 and gtm1.site2

Navigate to: DNS ›› Delivery : Profiles : Protocol : TCP

_images/dns_profile_tcp_flyout.png

Create a new TCP profile as shown in the following table.

Setting Value
Name example.com_tcp-dns_profile
Parent Profile f5-tcp-wan
_images/dns_profile_tcp.png

https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/dns/profile/tcp/create.jsp

https://gtm1.site2.example.com/tmui/Control/jspmap/tmui/dns/profile/tcp/create.jsp

TMSH Command for both gtm1.site and gtm1.site2:

TMSH

tmsh create ltm profile tcp example.com_tcp-dns_profile defaults-from tcp-wan-optimized

UDP IP Address

A UDP listener will receive and process DNS queries.

Note

It is required to complete the following task on both gtm1.site1 and gtm1.site2

Navigate to: DNS ›› Delivery : Listeners : Listener List

_images/listener_flyout.png

Create a UDP listener according to the following table:

Setting gtm1.site1 gtm1.site2
Name isp1_site1_ns1.example.com_udp_53_virtual isp1_site2_ns2.example.com_udp_53_virtual
Destination 203.0.113.8 198.51.100.40
Protocol Profile (Client) example.com_udp-dns_profile example.com_udp-dns_profile
DNS Profile example.com_dns_profile example.com_dns_profile

https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/dns/listener/create.jsp

https://gtm1.site2.example.com/tmui/Control/jspmap/tmui/dns/listener/create.jsp

_images/listener_settings.png

gtm1.site1 TMSH command:

TMSH

tmsh create gtm listener isp1_site1_ns1.example.com_udp_53_virtual address 203.0.113.8 ip-protocol udp mask 255.255.255.255 port 53 profiles add { example.com_dns_profile example.com_udp-dns_profile }

gtm1.site2 TMSH command:

TMSH

tmsh create gtm listener isp1_site2_ns2.example.com_udp_53_virtual address 198.51.100.40 ip-protocol udp mask 255.255.255.255 port 53 profiles add { example.com_dns_profile example.com_udp-dns_profile }

https://support.f5.com/csp/article/K14923

TCP IP Address

A TCP listener will receive and process DNS queries.

Note

It is required to complete the following task on both gtm1.site and gtm1.site2

Navigate to: DNS ›› Delivery : Listeners : Listener List

_images/listener_flyout.png

Create a TCP listener.

Setting gtm1.site1 gtm1.site2
Name isp1_site1_ns1.example.com_tcp_53_virtual isp1_site2_ns2.example.com_tcp_53_virtual
Destination 203.0.113.8 198.51.100.40
Protocol Profile (Client) example.com_tcp-dns_profile example.com_tcp-dns_profile
DNS Profile example.com_dns_profile example.com_dns_profile
_images/listener_tcp_settings.png

https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/dns/listener/create.jsp

https://gtm1.site2.example.com/tmui/Control/jspmap/tmui/dns/listener/create.jsp

gtm1.site1 TMSH command:

TMSH

tmsh create gtm listener isp1_site1_ns1.example.com_tcp_53_virtual address 203.0.113.8 ip-protocol tcp mask 255.255.255.255 port 53 profiles add { example.com_dns_profile example.com_tcp-dns_profile }

gtm1.site2 TMSH command:

TMSH

tmsh create gtm listener isp1_site2_ns2.example.com_tcp_53_virtual address 198.51.100.40 ip-protocol tcp mask 255.255.255.255 port 53 profiles add { example.com_dns_profile example.com_tcp-dns_profile }

https://support.f5.com/csp/article/K14923

Datacenters

Datacenters are logical groupings of devices that share a gateway.

Note

The tasks in this section are to be only completed on gtm1.site1

Navigate to: DNS > GSLB > Data Centers > Data Center List: Create

_images/create_datacenters_flyout.png

https://gtm1.site1.example.com/tmui/Control/jspmap/xsl/gtm_dc/list

Create two data centers according to the table below:

Setting Value
Name site1_datacenter
Name site2_datacenter
_images/create_datacenters.png

https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/globallb/data_center/create.jsp

TMSH command for only site1.gtm1:

TMSH

tmsh create gtm datacenter site1_datacenter

TMSH

tmsh create gtm datacenter site2_datacenter

Servers

Server objects need to be defined and grouped into a Datacenter

Navigate to: DNS ›› GSLB : Servers : Server List

_images/gslb_servers_flyout.png

https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/globallb/server/list.jsp

gtm1.site1

All GTM devices need to be defined. Create a server object for gtm1.site1

_images/server_create_none.png

Click “Create” to define gtm1.site1 as defined in the table below:

Setting Value
Name gtm1.site1_server
Data Center site1_datacenter
Devices Add: gtm1.site1.example.com : 203.0.113.7
Health Monitors bigip

  1. Fill in the Name and Datacenter

    _images/gtm1-click_add.png

  2. Click the “Add” button to define IP addresses

    _images/gtm1_click-addserver.png

  3. Complete the form and associate the “bigip” “Health Monitor”

    _images/gtm1.site1_create.png

https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/globallb/server/create.jsp

TMSH

tmsh create gtm server gtm1.site1_server datacenter site1_datacenter devices add { gtm1.site1.example.com { addresses add { 203.0.113.7 } } } monitor bigip product bigip

gtm1.site2

All GTM devices need to be defined. Create a server object for gtm1.site2

_images/server_create_gtm1.png

Click “Create” to define gtm1.site2 as defined in the table below:

Setting Value
Name gtm1.site2_server
Data Center site2_datacenter
Devices Add: gtm1.site2.example.com : 198.51.100.39
Health Monitors bigip

  1. Fill in the Name and Datacenter

    _images/gtm2-click_add.png

  2. Click the “Add” button to define IP addresses

    _images/gtm2_click-addserver.png

  3. Complete the form and associate the “bigip” “Health Monitor”

    _images/gtm1.site2_create.png

https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/globallb/server/create.jsp

TMSH

tmsh create gtm server gtm1.site2_server datacenter site2_datacenter devices add { gtm1.site2.example.com { addresses add { 198.51.100.39 } } } monitor bigip product bigip

site1_ha-pair

LTM devices need to be defined. Create a server object for the bigip1.site1 and bigip2.site1 HA pair

_images/server_create_gtm1-gtm2.png

Create a Server Object as defined in the table below:

Setting Value
Name site1_ha-pair
Data Center site1_datacenter
Devices Add: bigip1.site1.example.com : 203.0.113.5
Devices Add: bigip2.site1.example.com : 203.0.113.6
Health Monitors bigip
Virtual Server Discovery Enabled
Link Discovery Enabled

  1. Fill in the Name and Datacenter

    _images/site1_click-addserver.png

  2. Click the “Add” button to define IP addresses

    _images/site_ha_pair_bigip1_add.png

  3. Click “Add” again to define the other BIG-IP in the HA pair.

    _images/site1_click-addserver_again.png

  4. Click the “Add” button to define IP addresses

    _images/site_ha_pair_bigip2_add.png

  5. Complete the form and associate the “bigip” “Health Monitor”

    _images/site1-HA_pair_create.png

  6. Make sure to enable both “Virtual Server” and “Link” discovery

    _images/VS_and_link_auto_discovery.png

https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/globallb/server/create.jsp

TMSH

tmsh create gtm server site1_ha-pair datacenter site1_datacenter devices add { bigip1.site1.example.com { addresses add { 203.0.113.5 { } } } bigip2.site1.example.com { addresses add { 203.0.113.6 { } } } } link-discovery enabled monitor bigip product bigip virtual-server-discovery enabled

site2_ha-pair

LTM devices need to be defined. Create a server object for the bigip1.site2 and bigip2.site2 HA pair

_images/server_create_gtm1-gtm2-site1-hapair.png

Create a Server Object as defined in the table below:

Setting Value
Name site2_ha-pair
Data Center site2_datacenter
Device Add: bigip1.site2.example.com : 198.51.100.37
Device Add: bigip2.site2.example.com : 198.51.100.38
Health Monitors bigip
Virtual Server Discovery Enabled
Link Discovery Enabled

  1. Fill in the Name and Datacenter

    _images/site2_click-addserver.png

  2. Click the “Add” button to define IP addresses

    _images/site2_ha_pair_bigip1_add.png

  3. Click “Add” again to define the other BIG-IP in the HA pair.

    _images/site2_click-addserver_again.png

  4. Click the “Add” button to define IP addresses

    _images/site2_ha_pair_bigip2_add.png

  5. Complete the form and associate the “bigip” “Health Monitor”

    _images/site2-HA_pair_create.png

  6. Make sure to enable both “Virtual Server” and “Link” discovery

    _images/VS_and_link_auto_discovery.png

https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/globallb/server/create.jsp

TMSH

tmsh create gtm server site2_ha-pair datacenter site2_datacenter devices add { bigip1.site2.example.com { addresses add { 198.51.100.37 { } } } bigip2.site2.example.com { addresses add { 198.51.100.38 { } } } } link-discovery enabled monitor bigip product bigip virtual-server-discovery enabled

Device Trust

A mesh of F5 DNS servers need to exchange keys to establish a trusted mechanism for HA communications.

_images/establish_trust.png

Launch Putty and login to gtm1.site1.example.com

Run the following command:

When prompted for a password use “default”.

TMSH

bigip_add

_images/putty_gtm1_site1.png

Navigate to: DNS ›› GSLB : Servers : Trusted Server Certificates

https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/locallb/ssl_certificate/properties.jsp?certificate_name=server&store=iquery

_images/gslb_dataceter_servers_trusted_certificates.png

Sync Group

After the BIG-IP DNS server in datacenter 2 is joined to the sync group, administrators may make changes to either F5 DNS server.

Changes will be automatically replicated across all F5 DNS servers.

Launch Putty and log in to gtm1.site2

Run the following command: Enter the password “default” when prompted.

Select “y” to allow the bigip-ip to join the mesh.

TMSH

gtm_add 203.0.113.7

_images/putty_gtm1_site2.png

Pools

LTM virtual server objects are grouped together into GTM pools.

Navigate to: DNS ›› GSLB : Pools : Pool List

_images/gtm_pool_list.png

Create a Pool of LTM Virtuals according to the following table:

Setting Value
Name www.example.com_pool
Type A
member isp1_site1_www.example.com_tcp_https_virtual
member isp2_site2_www.example.com_tcp_https_virtual

https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/globallb/pool/create.jsp

_images/create_gtm_pool.png

TMSH command to run on only gtm1.site1:

TMSH

tmsh create gtm pool a www.example.com_pool { members add { site1_ha-pair:/Common/isp1_site1_www.example.com_tcp_https_virtual { member-order 0 } site2_ha-pair:/Common/isp2_site2_www.example.com_tcp_https_virtual { member-order 1 } } }

FQDN

F5 refers to an FQDN as a “wide-ip”, or “wip”.

Navigate to: DNS ›› GSLB : Wide IPs : Wide IP List

_images/gtm_wideip_list.png

Create an F5 “wide IP”

Setting Value
Name www.gslb.example.com
Type A
Pool www.example.com_pool
_images/gtm_wideip_create.png

https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/globallb/wideip/list.jsp

TMSH command to run on only gtm1.site1:

TMSH

tmsh create gtm wideip a www.gslb.example.com { pools add { www.example.com_pool { order 0 } } }

Delegation

Log in to the DNS server from the jumpbox (username: user pasword: Agility1) , and open the DNS management UI:

_images/dc01_dns_tools.png

A Records

Create two new A records for the new BIGP-IP nameservers.

Setting Value
ns1 203.0.113.8
ns2 198.51.100.40

Expand “Forward Lookup Zones”, right click on EXAMPLE.COM and select “New Host”

_images/dc01_new_A_ns2.png

Sub Domain

  1. Expand “Forward Lookup Zones”, and right click on “EXAMPLE.com

    _images/dc01_new_delegation.png

  2. Create the “gslb” subdomain.

    _images/dc01_new_delegation_create_gslb.png

  3. Step through the Delegation Wizard. Add “ns1.example.com - 203.0.113.8”

    _images/dc01_new_delegation_ns1ns2.png

  4. Also add “ns2.example.com - 198.51.100.40”

    _images/dc01_new_delegation_ns1ns2_create.png

  5. Make sure both ns1.example.com and ns2.example.com are added

    _images/dc01_new_delegation_ns1ns2_create_finish.png

  6. Click “Finish”

    _images/dc01_new_delegation_create_gslb_finish.png

CNAME

  1. Make sure “Forward Lookup Zones” and “EXAMPLE.COM” is expanded. Right click on “www”, and select delete.

    _images/dc01_new_delegation_delete_www.png

  2. Right click on “EXAMPLE.COM”, and select “New Alias (CNAME)”

    _images/dc01_new_delegation_create_cname.png

  3. Add “www - www.gslb.example.com”

    _images/dc01_new_delegation_create_cname_finish.png

Results

  1. From the Workstation command prompt type “dig www.example.com”

    _images/dc01_new_delegation_create_cname_results.png

  2. Observe WIDEIP statistics on gtm1.site1: Statistics ›› Module Statistics : DNS : GSLB ›› Wide IPs : www.gslb.example.com : A

    https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/globallb/stats/wideip/stats_detail.jsp?name=%2FCommon%2Fwww.gslb.example.com&type=1&identity=www.gslb.example.com+%3A+A

    _images/gtm1_site1_wideip_statistics_flyout.png _images/gtm1_site1_wideip_statistics_detail.png

    TMSH

    tmsh show gtm wideip a www.gslb.example.com

  3. Observe WIDEIP statistics on gtm1.site2: Statistics ›› Module Statistics : DNS : GSLB ›› Wide IPs : www.gslb.example.com : A

    https://gtm1.site2.example.com/tmui/Control/jspmap/tmui/globallb/stats/wideip/stats_detail.jsp?name=%2FCommon%2Fwww.gslb.example.com&type=1&identity=www.gslb.example.com+%3A+A

  4. Disable physical interfaces on gtm1.site2:

    https://gtm1.site2.example.com/tmui/Control/form?__handler=/tmui/locallb/network/interface/list&__source=disable&__linked=false&__fromError=false

    _images/gtm1_site1_disable_interfaces.png

    TMSH command to run on only gtm1.site2:

    TMSH

    tmsh modify net interface all disabled

  5. Refresh statistics on gtm1.site1 and make sure DNS requests are still resolving.

    https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/globallb/stats/wideip/stats_detail.jsp?name=%2FCommon%2Fwww.gslb.example.com&type=1&identity=www.gslb.example.com+%3A+A

  6. Re-enable interfaces on gtm1.site2, disable interfaces on gtm1.site1. Observe statistics on gtm1.site2 and make sure DNS requests are still resolving.

    TMSH command to run on only gtm1.site2:

    TMSH

    tmsh modify net interface all enabled

  7. Observe pool statistics on gtm1.site1: Statistics ›› Module Statistics : DNS : GSLB ›› Pools : www.example.com_pool : A

    https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/globallb/stats/pool/stats_detail.jsp?name=%2FCommon%2Fwww.example.com_pool&pool_type=1&identity=www.example.com_pool+%3A+A

    _images/results_pool_statistics.png

    TMSH

    show gtm pool a www.example.com_pool

  8. Using Putty, ssh into gtm1.site1 and run the following command to watch logs:

    TMSH

    tail -f /var/log/ltm

Persistence

Modify the GSLB configuration so that LDNS servers continually receive the same DNS answer.

  1. On gtm1.site1 navigate to: DNS ›› GSLB : Pools : Pool List ›› Members : www.example.com_pool

    _images/gslb_wideip_list.png

    https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/globallb/wideip/list.jsp

  2. Click into the “Pools” tab:

    _images/gslb_wideip_list_members.png

    https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/globallb/wideip/pools.jsp?name=%2FCommon%2Fwww.gslb.example.com&type=1&identity=www.gslb.example.com

  3. Enable Persistence

    _images/gslb_wideip_persistence_enabled.png

    TMSH

    tmsh modify gtm wideip a www.gslb.example.com persistence enabled

  4. View Persistence Records

    TMSH

    tmsh show gtm persist

LB Methods

Modify the GSLB configuration so that site2 is a standby DR site.

Introduce a network problem that causes the isp1 link monitor to fail.

An ISP network outage can automatically cause DR activation.

  1. On gtm1.site1 navigate to: DNS ›› GSLB : Pools : Pool List ›› Members : www.example.com_pool

    https://gtm1.site1.example.com/tmui/Control/jspmap/tmui/globallb/pool/members.jsp?name=%2FCommon%2Fwww.example.com_pool&pool_type=1&identity=www.example.com_pool

    _images/gslb_pool_persistence_flyout.png

  2. Modify the “Load Balancing Method” -> “Preferred” to “Global Availability”

    _images/gslb_pool_global_availability_details.png

    TMSH

    tmsh modify gtm pool a www.example.com_pool load-balancing-mode global-availability

  3. Introduce a network problem in the ISP at site1

    Log into the router and disable interface 1.6 connecting ISP1 to site1

    https://router01.branch01.example.com/tmui/Control/jspmap/tmui/locallb/network/interface/list.jsp

    _images/router_disable_isp1_site_interface.png

    TMSH command to run on the router01 to simulate an ISP failure

    TMSH

    tmsh modify interface 1.6 disabled

  4. View the effect

    Log into gtm1.site2 and observe the status of “Link” objects:

    _images/dns_gslb1_site2_links.png

    https://gtm1.site2.example.com/tmui/Control/jspmap/xsl/gtm_link/list

    TMSH

    tmsh show gtm link

  5. Set the site1 isp link back up

    Log into the router and enable the interface 1.6 connecting ISP1 to site1

    https://router01.branch01.example.com/tmui/Control/jspmap/tmui/locallb/network/interface/list.jsp

    _images/router_enable_isp1_site_interface.png

    TMSH

    tmsh modify interface 1.6 enabled

Note: Even though you re-enabled the primary site1, a persistence record from the previous lab is still in place.

Class 2 - Advanced GSLB

The lab environment consists of a Lan of workstations in a remote location with internal DNS servers behind an F5 firewall.

The F5 device is directly connected to the internet.

_images/class2_overview.png

Students will work with the following concepts as part of a group of lab exercises.

  1. Transparent Cache
  2. Hidden Master
  3. DNSSec
  4. Validating Resolver
  5. RPZ
  6. URL Categorization

Transparent Cache

Monitors

A DNS application specific health monitor provides intelligence in the steering DNS queries towards the fastest responding DNS server.

_images/class2_dc02_is_down.png

Navigate to: Delivery : Load Balancing : Monitors

_images/class2_create_health-monitor_flyout.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/monitor/list.jsp

Create a monitor according to the following table:

Setting Value
Name example.com_dns_monitor
Type DNS
Query Name www.example.com
_images/class2_dns_monitor_create_properties.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/monitor/create.jsp

TMSH

tmsh create ltm monitor dns example.com_dns_monitor defaults-from dns qname www.example.com

Load Balancing

Augment and scale an existing DNS infrastructure by Load Balancing DNS queries across a pool of DNS servers.

Navigate to: Delivery : Load Balancing : Pools : Pool List

_images/class2_dns__pool_create_flyout.png

Create a pool according to the following table:

Setting Value
Name branch01_dns_pool
Health Monitors example.com_dns_monitor
  1. Node Name
 dc01.branch01.example.com_node
  1. Address
 10.1.70.200
  1. Service Port
 53
  1. Node Name
 dc02.branch01.example.com_node
  1. Address
 10.1.70.210
  1. Service Port
 53
_images/class2_create_dns_pool_properties.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/pool/create.jsp

TMSH

tmsh create ltm pool branch01_dns_pool members add { dc01.branch01.example.com_node:53 { address 10.1.70.200 } dc02.branch01.example.com_node:53 { address 10.1.70.210 } } monitor example.com_dns_monitor

Results

  1. Navigate to: DNS ›› Delivery : Load Balancing : Pools : Pool List

    Click to select the branch01_dns_pool, and then click “Members”

    _images/class2_cache_listpool_flyout.png

    https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/pool/list.jsp

  2. Click to select “branch01_dns_pool”, and then select “Members”

    _images/class2_click-members_pool.png

    https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/pool/resources.jsp?name=/Common/branch01_dns_pool

  3. Notice the health status of the existing DNS infrastructure.

    _images/class2_ltmpool_wthone_down_member.png

    TMSH

    tmsh show ltm pool branch01_dns_pool detail

    _images/class2_dc02_is_down.png

In this module we will prepare the objects required to build a transparent cache.

In the next exercise a DNS profile will reference the cache and a Listener will forward traffic to a healthy backend DNS server

_images/before_transparent_cache.png

Enabling a transparent cache on the BIG-IP will offload some DNS queries from being sent to the internal DNS servers.

_images/transparent_cache_enabled.png

Log into the gateway device router01.brancho1 in the branch office

Navigate to DNS ›› Caches : Cache List

Create a transparent cache

Setting Value
Name transparent_cache
Resolver Type Transparent
_images/cache_transparent.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/cache/create.jsp

TMSH command for router01.branch01:

TMSH

tmsh create ltm dns cache transparent transparent_cache

Listeners

A listener object is an specialized virtual server that is configured to respond to DNS queries.

We will be creating both TCP and UDP based listeners that have the same IP address of the existing DNS server.

Note: the Workstation is configured to use 10.1.70.200 and 10.1.70.210 for DNS.

After this module students will have enabled the BIG-IP to intercept and cache DNS requests.

_images/class2_create_listenerVIPS.png

Log Profile

Configure DNS query and response logging.

  1. Create a “Log Publisher” for local syslog.

    Navigate to: System ›› Logs : Configuration : Log Publishers

    _images/system_log_publisher_flyout.png

    Create a local syslog publisher as shown in the table below:

    Setting Value
    Name local-syslog-publisher
    Destinations local-syslog
    _images/sys_syslog_publisher_details.png

    https://router01.branch01.example.com/tmui/Control/jspmap/tmui/system/log/create_publisher.jsp

    TMSH

    tmsh create sys log-config publisher local-syslog-publisher { destinations add { local-syslog { } } }

  2. Create a “Logging Profile”

    Navigate to DNS ›› Delivery : Profiles : Other : DNS Logging

    _images/dns_cache_transparent_flyout_router01.png

    Create a DNS logging profile as shown in the table below:

    Setting Value
    Name example_dns_logging_profile
    Log Publisher local-syslog-publisher
    Log Responses enabled
    Include Query ID enabled
    _images/dns_cache_transparent_create_router01.png

    https://router01.branch01.example.com/tmui/Control/jspmap/tmui/locallb/profile/dns_log/create.jsp

    TMSH

    tmsh create ltm profile dns-logging example_dns_logging_profile enable-response-logging yes include-query-id yes log-publisher local-syslog-publisher

DNS Profile

A DNS profile will control which features are enabled as part of processing a query.

Navigate to: DNS ›› Delivery : Profiles : DNS

_images/router01_ltm_profile_dns.png

Create a DNS profile as shown in the table below.

Setting Value
Name example.com_dns_profile
DNS Cache Enabled
DNS Cache Name transparent_cache
Use BIND Server on Big-IP Disabled
Logging Enabled
Logging Profile example_dns_logging_profile
AVR statistics Sample Rate Enabled, 1/1 queries sampled
_images/dns_profile_settings_cache_router01.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/locallb/profile/dns/create.jsp

TMSH

tmsh create ltm profile dns example.com_dns_profile { avr-dnsstat-sample-rate 1 cache transparent_cache defaults-from dns enable-cache yes enable-logging yes log-profile example_dns_logging_profile use-local-bind no }

UDP Profile

A UDP profile controls the way the platform processes UDP traffic.

Navigate to: DNS ›› Delivery : Profiles : Protocol : UDP

_images/router01_create_udp_profile.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/profile/udp/list.jsp

Create a UDP profile as shown in the following table.

Setting Value
Name example.com_udp-dns_profile
Parent Profile udp_gtm_dns
_images/router01_create_udp_profile_properties.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/profile/udp/create.jsp

TMSH

tmsh create ltm profile udp example.com_udp-dns_profile defaults-from udp_gtm_dns

TCP Profile

A TCP profile controls the way the platform processes TCP traffic.

Navigate to: DNS ›› Delivery : Profiles : Protocol : TCP

_images/router01_create_tcp_profile.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/profile/tcp/list.jsp

Create a TCP profile as shown in the following table.

Setting Value
Name example.com_tcp-dns_profile
Parent Profile f5-tcp-lan
_images/router01_create_tcp_profile_properties.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/profile/tcp/create.jsp

TMSH

tmsh create ltm profile tcp example.com_tcp-dns_profile defaults-from f5-tcp-lan

UDP Listener

A UDP listener is an IP address that will receive DNS queries.

Navigate to: DNS ›› Delivery : Listeners : Listener List

_images/router01_create_virtual_flyout.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/listener/list.jsp

Create two UDP listeners according to the tables below:

Setting Value
Name DC01_udp_53_virtual
Destination Address 10.1.70.200
Service Port DNS 53
VLAN and Tunnel Traffic -> Enabled on.. branch01_vlan
Protocol UDP
Protocol Profile (Client) example.com_udp-dns_profile
DNS Profile example.com_dns_profile
Default Pool branch01_dns_pool
Setting Value
Name DC02_udp_53_virtual
Destination Address 10.1.70.210
Service Port DNS 53
VLAN and Tunnel Traffic -> Enabled on.. branch01_vlan
Protocol UDP
Protocol Profile (Client) example.com_udp-dns_profile
DNS Profile example.com_dns_profile
Default Pool branch01_dns_pool
_images/router01_create_virtual_udp_properties.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/locallb/virtual_server/create.jsp

TMSH

tmsh create gtm listener DC01_udp_virtual address 10.1.70.200 port 53 ip-protocol udp pool branch01_dns_pool profiles add { example.com_dns_profile example.com_udp-dns_profile } vlans add { branch01_vlan } vlans-enabled

TMSH

tmsh create gtm listener DC02_udp_virtual address 10.1.70.210 port 53 ip-protocol udp pool branch01_dns_pool profiles add { example.com_dns_profile example.com_udp-dns_profile } vlans add { branch01_vlan } vlans-enabled

TCP Listeners

A TCP listener is an IP address that will receive DNS queries.

Navigate to: DNS ›› Delivery : Listeners : Listener List

_images/router01_create_virtual_flyout.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/listener/list.jsp

Create two TCP listeners according to the table below:

Setting Value
Name DC01_tcp_53_virtual
Destination 10.1.70.200
Service Port DNS 53
VLAN and Tunnel Traffic -> Enabled on.. branch01_vlan
Protocol TCP
Protocol Profile (Client) example.com_tcp-dns_profile
DNS Profile example.com_dns_profile
Pool branch01_dns_pool
Setting Value
Name DC02_tcp_53_virtual
Destination 10.1.70.210
Service Port DNS 53
VLAN and Tunnel Traffic -> Enabled on.. branch01_vlan
Protocol TCP
Protocol Profile (Client) example.com_tcp-dns_profile
DNS Profile example.com_dns_profile
Pool branch01_dns_pool
_images/router01_create_virtual_tcp_properties.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/listener/create.jsp

TMSH

tmsh create gtm listener DC01_tcp_virtual address 10.1.70.200 port 53 ip-protocol tcp pool branch01_dns_pool profiles add { example.com_dns_profile example.com_tcp-dns_profile } vlans add { branch01_vlan } vlans-enabled

TMSH

tmsh create gtm listener DC02_tcp_virtual address 10.1.70.210 port 53 ip-protocol tcp pool branch01_dns_pool profiles add { example.com_dns_profile example.com_tcp-dns_profile } vlans add { branch01_vlan } vlans-enabled

https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/bigip-dns-cache-implementations-11-3-0/2.html

Results

  1. From the jumpbox open a command prompt, perform several recursive queries to your new listener to test.

    Repeat some of the same queries multiple times

    dig www.f5.com
dig www.wikipedia.org
dig www.ncsu.edu
dig www.example.com

  2. Viewing Cache Entries

    Navigate to: DNS ›› Caches : Cache List ›› Properties : transparent_cache

    _images/router01_cache_select_statistics.png

    https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/cache/properties.jsp?name=%2FCommon%2Ftransparent_cache

    Navigate to: Statistics ›› Module Statistics : DNS : Caches ›› Caches

    _images/router01_cache_click_view.png

    Navigate to: Statistics ›› Module Statistics : DNS : Caches ›› Caches : transparent_cache

    _images/router01_cache_view_details.png

    https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/cache/stats_detail.jsp?name=/Common/transparent_cache

    TMSH

    tmsh show ltm dns cache records rrset cache transparent_cache

    _images/tmsh_show_ltm_dns_cache_records.png

    TMSH

    show ltm dns cache transparent transparent_cache

  3. Clearing Entire Cache

    Navigate to Statistics > Module Statistics > DNS > Caches

    Set “Statistics Type” to “Caches”.

    Select the cache and click “Clear Cache” to empty the cache.

Hidden Master

The internal DNS servers are authoritative for example.com so we need to slave the zone to the BIG-IP.

After this module is complete the BIG-IP will become an authoritative slave.

_images/class2_hidden_masters.png

https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/dns-services-implementations-11-6-0/2.html#unique_1658664851

Name Server

Define the Active Directory server as a nameserver and initiate a zone transfer.

Navigate to DNS ›› Delivery : Nameservers : Nameserver List

_images/create_nameserver_flyout.png

Create a nameserver according to the following table:

Setting Value
Name dc01.example.com
Address 10.1.70.200
_images/create_nameserver_dc01.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/nameserver/create.jsp

TMSH

tmsh create ltm dns nameserver dc01.example.com { address 10.1.70.200 }

DNS Express

The zone example.com is served from the high performance authoritative resolver.

Navigate to DNS ›› Zones : Zones : Zone List

_images/create_dnsxpress_flyout.png

Create a DNS Express zone according to the following table:

Setting Value
Name example.com
Server dc01.example.com
Allow NOTIFY From 10.1.70.200
_images/create_dnsxpress_zone_example.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/zone/create.jsp

TMSH

tmsh create ltm dns zone example.com { dns-express-allow-notify add { 10.1.70.200 } dns-express-notify-tsig-verify no dns-express-server dc01.example.com }

https://support.f5.com/kb/en-us/products/big-ip-dns/manuals/product/bigip-dns-services-implementations-12-1-0/1.html#guid-977cd16a-5d12-4b1e-964c-5d8206f647ed

Results

The BIG-IP will now be an authoratative slave for the example.com zone. This protects the master as well as increases performance utilizing the BIG-DNS delivery engine.

  1. Click on the newly created DNS Express zone and make sure it is showing green for ‘Available’ indicating that the initial AXFR transfer was successful.

    _images/DNS_Express_result1.png

  2. Using putty from the taskbar, log in to router01.branch01.example.com.

Run the following command to see the contents of the DNS Express database:

dnsxdump | less

Examine the results

_images/DNS_Express_result3.png

DNSSec

_images/dnssec_zone_sign.png

https://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/dns-services-implementations-11-6-0/2.html#unique_1658664851

Zone Signing Key

Navigate to: DNS ›› Delivery : Keys : DNSSEC Key List

_images/dnssec-keys-create.png

Create zone signing key according the following table:

Setting Value
Name example.com_zsk
Type Zone Signing Key
Key Management Manual
Certificate default.crt
Private Key default.key
_images/dnssec-zsk.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/dnssec_key/create.jsp

TMSH

tmsh create ltm dns dnssec key example.com_zsk key-type zsk certificate-file default.crt key-file default.key

Key Signing Key

Navigate to: DNS ›› Delivery : Keys : DNSSEC Key List

_images/dnssec-keys-create.png

Create a key signing key according to the following table:

Setting Value
Name example.com_ksk
Type Key Signing Key
Key Management Manual
Certificate default.crt
Private Key default.key
_images/dnssec-ksk.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/dnssec_key/create.jsp

TMSH commands for Key Signing key creation:

TMSH

tmsh create ltm dns dnssec key example.com_ksk key-type ksk certificate-file default.crt key-file default.key

Signed Zone

Navigate to: DNS ›› Zones : DNSSEC Zones : DNSSEC Zone List

_images/dnssec-zone.png

https://router01.branch01.example.com/tmui/Control/form?__handler=/tmui/dns/dnssec_zone/list&__source=delete_confirm&__linked=false&__fromError=false

Create DNS Express zone signed by DNSSEC

Setting Value
Name example.com
Zone Signing Key example.com_zsk
Key Signing Key example.com_ksk
_images/dnssec-new-zone.png

TMSH commands for DNSSEC signed zone creation:

TMSH

tmsh create ltm dns dnssec zone example.com keys add { example.com_ksk example.com_zsk }

Results

From the CLI on the router01.branch01 BIGIP run tail -f /var/log/ltm

From the Workstation CMD prompt run: “dig example.com +dnssec”

_images/dnssec-logs.png

Validating Resolver

Trust Anchors

Create a trust anchor to validate content in a DNS response.

Using Putty, ssh into router01.branch01 and run the following command:

TMSH

dig dnskey . | grep 257 > /root/dnskey.txt

dnssec-dsfromkey -f /root/dnskey.txt .

_images/trusted-anchors-cli.png

Navigate to: DNS ›› Caches : Cache List ›› validating-resolver_cache : Trust Anchors

Select the validating-resolver_cache and click “Trust Anchors”

_images/selet_validating_resolver.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/cache/trust_anchor/list.jsp?name=%2FCommon%2Fvalidating-resolver_cache&tab=dns_cache_validating_config

_images/trust-anchor.png

For each line of output from the preceding command create a “Trust Anchor”

_images/trust-ancor-1.png _images/trusted-anchors-done.png 
1
tmsh modify ltm dns cache validating-resolver validating-resolver_cache trust-anchors replace-all-with { ". IN DS 19036 8 1 B256BD09DC8DD59F0E0F0D8541B8328DD986DF6E" ". IN DS 19036 8 2 49AAC11D7B6F6446702E54A1607371607A1A41855200FD2CE1CDDE32F24E8FB5" ". IN DS 20326 8 1 AE1EA5B974D4C858B740BD03E3CED7EBFCBD1724" ". IN DS 20326 8 2 E06D44B80B8F1D39A95C0B0D7C65D08458E880409BBC683457104237C7F8EC8D" }

Modify DNS Profile

In order to activate the new “Validating Resolver”, modify the DNS profile example.com_dns_profile.

Navigate to: DNS ›› Delivery : Profiles : DNS

_images/modify_dns_profile_activate_validating_resolver.png

Select the profile “example.com_dns_profile”

Modify the DNS profile to activate the new validating-resolver_cache.

_images/modify_dns_profile_validating_resolver.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/profile/dns/properties.jsp?name=/Common/example.com_dns_profile

TMSH

tmsh modify ltm profile dns example.com_dns_profile cache validating-resolver_cache

Results

From the CLI on the router01.branch01 BIGIP run

tail -f /var/log/ltm

From the Workstation CMD prompt run: “dig ghghghghg.com”

_images/nxdomain.png

From the Workstation CMD prompt run: “dig google.com”

_images/google.png

From the Workstation CMD prompt run: “dig dnssec-deployment.org +dnssec”

_images/dnssec-resolver-results.png

From the Workstation CMD prompt run: “dig dnssec-failed.org +dnssec”

_images/dnssec-failed.png

http://www.internetsociety.org/deploy360/resources/dnssec-test-sites/

Configure a validating resolver cache on the BIG-IP® system to recursively query public DNS servers, validate the identity of the DNS server sending the responses, and then cache the responses.

After completing this lab students will entirely offload DNS queries from internal masters.

_images/class2_validating-resolver.png _images/class2_validating-resolver2.png

Navigate to DNS ›› Caches : Cache List

_images/cache_list_flyout.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/cache/list.jsp

Create a validating resolver cache according to the table below:

Setting Value
Name validating-resolver_cache
Resolver Type Validating Resolver
Answer default zones Checked - Enabled
_images/cache_validating-resolver.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/cache/create.jsp

TMSH

tmsh create ltm dns cache validating-resolver validating-resolver_cache answer-default-zones yes

https://support.f5.com/kb/en-us/products/big-ip-dns/manuals/product/bigip-dns-services-implementations-12-1-0/7.html#guid-d4548549-b4e2-4dae-9ada-3ea00eb84c1f

RPZ

Response Policy Zone will be turned on to stop clients from trying to resolve blacklisted domains.

_images/class2_rpz_overview.png

https://support.f5.com/kb/en-us/products/big-ip-dns/manuals/product/bigip-dns-services-implementations-12-1-0/8.html

Zone Runner

Customers will subscribe to their RPZ vendor of choice.

Use Zonerunner to create a custom RPZ zone for our lab.

Navigate to DNS ›› Zones : ZoneRunner : Zone List

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/globallb/zfd/zone/create.jsp

_images/zonerunner_create_zone.png

Create a zone according to the following table:

Setting Value
View Name external
Zone Name rpz.example.com
Zone Type Master
Zone File Name db.external.rpz.example.com
Options also-notify { ::1 port 5353; };
TTL 300
Master Server router01.branch01.example.com.
Email Contact hostmaster.example.com.
NS Record: TTL 300
NS Record: Nameserver router01.branch01.example.com.
Create A Record Checked - Enabled
A Record: IP Address 10.1.71.1
_images/zonerunner_create_zone_properties.png

Navigate to: DNS ›› Zones : ZoneRunner : Resource Record List

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/globallb/zfd/record/create.jsp

_images/zonerunner_create_resource_record.png

Create a resource record according to the following table:

Setting Value
View Name external
Zone Name rpz.example.com
Name *.guns.com.rpz.example.com.
TTL 300
Type CNAME
CNAME .
_images/zonerunner_create_resource_record_properties.png _images/zonerunner_list_resource_records.png

Name Server

Navigate to DNS ›› Delivery : Nameservers : Nameserver List

_images/create_nameserver_flyout.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/nameserver/list.jsp

Create a nameserver according to the following table:

Setting Value
Name localhost
_images/create_nameserver_localhost.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/nameserver/create.jsp

TMSH

tmsh create ltm dns nameserver localhost { address 127.0.0.1 tsig-key none }

DNS Express

Navigate to DNS ›› Zones : Zones : Zone List

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/zone/create.jsp

_images/create_dnsxpress_flyout.png

Create a DNS Express zone according to the following table:

Setting Value
Name rpz.example.com
Server localhost
Allow NOTIFY From 127.0.0.1
Response Policy checked
_images/create_dnsxpress_zone.png

TMSH

tmsh create ltm dns zone rpz.example.com { dns-express-server localhost response-policy yes dns-express-allow-notify add { 127.0.0.1 } dns-express-notify-tsig-verify no }

Local Zone

Navigate to: DNS ›› Caches : Cache List

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/cache/list.jsp

_images/select_validating-resolver_cache.png

Select validating-resolver_cache, click “Local Zones”, and click “Add”

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/cache/local_zone/list.jsp?name=%2FCommon%2Fvalidating-resolver_cache&tab=dns_cache_config

_images/cache_create_local-zone.png

Create a local zone entry according to the following table:

Setting Value
Name sorry.example.com
Type Static
Records sorry.example.com. IN A 10.1.71.21
_images/create_localzone_entry.png

TMSH commands for router01.branch01:

tmsh modify ltm dns cache validating-resolver validating-resolver_cache local-zones { { name sorry.example.com records add { "sorry.example.com. IN A 10.1.71.21" } type static } }

Walled Garden

Navigate to: DNS ›› Caches : Cache List

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/cache/list.jsp

Click “validating-resolver_cache”

_images/select_validating-resolver_cache.png

Select validating-resolver_cache, click “Response Policy Zones”, and then click “Add”

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/cache/rpz/list.jsp?name=%2FCommon%2Fvalidating-resolver_cache&tab=dns_cache_config

_images/cache_enable_rpz.png

Create a local zone entry according to the following table:

Setting Value
Zone rpz.example.com
Action Walled Garden
Walled Garden sorry.example.com
_images/cache_enable_rpz_details.png

TMSH commands for router01.branch01:

TMSH

tmsh modify ltm dns cache resolver validating-resolver_cache response-policy-zones add { rpz.example.com { action walled-garden walled-garden sorry.example.com } }

Results

From a Workstation command prompt run “dig www.guns.com”

_images/cmd_dig_guns_rpz.png

Try running additional dig commands to verify that other domains still resolve as expected.

dig www.f5.com

URL Categorization

Configure DNS queries filtering based on the category of the requested domain. This will be done with using F5 iRules and built-in categorization database.

_images/url_categorization.png

Create an iRule

Navigate to: DNS ›› Delivery : iRules : iRules List

_images/irule-new.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/rule/list.jsp

Create new iRule, copy the content below and paste it.

Setting Value
Name DNS-query-filtering 
when RULE_INIT {
  # Set categories to block for DNS hosts
  set static::blocked_categories {
    /Common/Bot_Networks
    /Common/Spyware
    /Common/Malicious_Web_Sites
    /Common/Adult_Content
    /Common/Sex
  }


  # CONFIGURATION
  # Check all requests by default
  set static::request_check 1
  # If the category returns as blocked, return NXDOMAIN (1)
  # Otherwise if (0), return a statically defined IP address
  set static::request_return_nxdomain 0
  set static::request_redirect_to "10.1.71.21"
  # Toggle for debug logs
  set static::request_debug 1
}


when DNS_REQUEST {
  if { $static::request_check } {
    set lookup_category [getfield [CATEGORY::lookup "http://[DNS::question name]"] " " 1]
    if { [lsearch -exact $static::blocked_categories $lookup_category] >= 1 } {
      if { $static::request_debug } {
         log local0. "BLOCKED: Category $lookup_category matching [DNS::question name] is filtered."
      }
      DNS::answer clear
      if { $static::request_return_nxdomain } {
         DNS::header opcode QUERY
         DNS::header rcode NXDOMAIN
      } else {
         if { [DNS::question type] equals "A" } {
            DNS::answer insert "[DNS::question name]. 111 [DNS::question class] [DNS::question type] $static::request_redirect_to"
         }
      }
      DNS::return
 } else {
   if { $static::request_debug } {
      log local0. "Category $lookup_category matching [DNS::question name] is not filtered"
      }
    }
  }
}

TMSH commands for router01.branch01 (Make sure you use text editor to copy content above and paste it)

TMSH

tmsh create ltm rule DNS-query-filtering

iRule assignment

Repeat the following steps for all 4 DNS listeners.

Navigate to: DNS ›› Delivery : Listeners : Listener List

_images/listener-assignment-1.png

Navigate to the listener DC01_udp_virtual

_images/listener-assignment-2-c.png

Navigate to iRules section

_images/irule-assignment-3-c.png

Navigate to Manage

_images/irule-assignment-4-c.png

https://router01.branch01.example.com/tmui/Control/form?__handler=/tmui/dns/listener/irules&__source=Manage…&__linked=false&__fromError=false

Highlight DNS-query-filtering iRule and move it to Selected column

_images/irule-assignment-5-c.png

TMSH commands for router01.branch01

TMSH

tmsh modify gtm listener all rules { DNS-query-filtering }

Results

From the CLI on the router01.branch01 BIGIP run

tail -f /var/log/ltm

From the Workstation command prompt run “dig example.com” and check for the results

_images/examplecom.png

From the Workstation command prompt run “dig porno.com” and check for the results

_images/pornocom.png

Navigate to: DNS ›› Delivery : iRules : iRules List

_images/irule-new.png

https://router01.branch01.example.com/tmui/Control/jspmap/tmui/dns/rule/list.jsp

Click on the DNS-query-filtering iRule and add new filtering category “News_and_Media”

_images/news.png

From the Workstation command prompt run “dig cnn.com” and check for the results

_images/cnn.png

Credits

  • Agility 2017:

    Bill Wester

    Boris Gekhtman

    Brendan Gladney

    Brian Buback

    Emilio Torres

    Dave Doucette

    Josh Anderson

    Robin Mordasiewicz

  • Advisors:

    Hitesh Patel

    Joe Hermes

    Jonathan Dehaan

    Pat Chang

    Pat Fiorino

    Brian Van Lieu