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F5 Big-IP Advanced Troubleshooting

I work with F5 since many years and I always need some advanced troubleshooting tools which I documented here a little bit.

CLI Commands

Show pool members monitoring status

tmsh show ltm pool all members field-fmt | grep -P "(ltm\ pool|active-member-cnt|addr|monitor-status)"

Count pool members with monitoring status "monitor-status\ checking"

tmsh show ltm pool all members field-fmt | grep "monitor-status\ checking" | wc -l

Show Health Monitor status

Example with ICMP health monitor:

tmsh show ltm monitor icmp icmp

Answer:
Destination:  1.7.3.55:0
   State time:   up for 527hrs:54mins:45sec
  |   Last error:   N/A @2019.11.12 10:58:51

  Destination:  1.7.3.56:0
   State time:   up for 527hrs:54mins:45sec
  |   Last error:   N/A @2019.11.12 10:58:51

  Destination:  1.7.3.131:0
   State time:   down for 527hrs:54mins:45sec
  |   Last error:   No successful responses received before deadline. @2019.11.12 10:58:51

  Destination:  1.7.3.139:0
   State time:   down for 527hrs:54mins:45sec
  |   Last error:   No successful responses received before deadline. @2019.11.12 10:58:51

Displaying and deleting connection table entries from the command line

The BIG-IP connection table contains information about all the sessions that are currently established on BIG-IP system. You can display and delete the contents of the BIG-IP connection table from the command line using the tmsh connection command.

Important:  On systems with a large number of connections, executing the following commands with a large output may result in excessive output causing device instability.  It is recommended you limit the output to specific IP address and/or port combination as demonstrated in the examples below.

Display Connection Table Entries: 

  1. To display the BIG-IP connection table entries for a particular virtual server, use the following tmsh command syntax: 

    tmsh show /sys connection cs-server-addr <vs_ip> cs-server-port <vs_port>     
    For example, to display the BIG-IP connection table entries for 10.10.2.2:443 virtual server, you would type the following command: 

    tmsh show /sys connection cs-server-addr 10.10.2.2 cs-server-port 443
  2. To display the BIG-IP connection table entries for a particular client IP address, use the following tmsh command syntax: 

    tmsh show /sys connection cs-client-addr <client_ip>
    For example, to display the BIG-IP connection table entries for 10.10.20.2 client IP address, you would type the following commnad: 

    tmsh show /sys connection cs-client-addr 10.10.20.2
  3. To display the BIG-IP connection table entries for a particular pool member, use the following tmsh command syntax: 

    tmsh show /sys connection ss-server-addr <pool_member_ip> ss-server-port <pool_member_port>
    For example, to display the BIG-IP connection table entries for 192.168.10.2:80 pool member, you would type the following command: 

    tmsh show /sys connection ss-server-addr 192.168.10.2 ss-server-port 80
  4. To display additional information about particular connection such as Idle timeout, number of packets sent etc, use the following tmsh command syntax: 

    tmsh show /sys connection cs-client-addr <client_ip> cs-client-port <client_port> cs-server-addr <vs_ip> cs-server-port <vs_port> all-properties
    For example, to display specific details of connection established between 10.10.20.2:51435 (client) and 10.10.2.2:443 (virtual server), you would type the following command: 

    tmsh show /sys connection cs-client-addr 10.10.20.2 cs-client-port 51435 cs-server-addr 10.10.2.2 cs-server-port 443 all-properties

Delete the connection table entries:

  1. To delete the BIG-IP connection table entries for a particular client IP and virtual server, use the following tmsh command syntax: 

    tmsh delete /sys connection cs-client-addr <client_ip> cs-server-addr <vs_ip> cs-server-port <vs_port>
    For example, to delete the BIG-IP connection table entries for 10.10.20.2 client IP address and 10.10.2.2:443 virtual server, you would type the following command: 

    tmsh delete /sys connection cs-client-addr 10.10.20.2 cs-server-addr 10.10.2.2 cs-server-port 443

F5 Support Solution Link

K53851362: Displaying and deleting BIG-IP connection table entries from the command line

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