Forum Discussion

Chandru_14793's avatar
Chandru_14793
Icon for Nimbostratus rankNimbostratus
Feb 25, 2011

Custom UDP Monitor

 

I need to create a custom UDP monitor, which can Send an input string and waits for a particular output string.

 

 

I went to LocalTraffic->Monitors>create newMonitor>UDP

 

 

Under Advanced section, I see Send String under it. I dont see Receive string which can verify the output

 

 

how can I get the Receive String populated

 

 

We have an server pool which responds to udp queries (Not DNS or NTP). We need to verify the output and remove the server from the pool based on reply strings
config
design
  • hoolio's avatar
    hoolio
    Icon for Cirrostratus rankCirrostratus
    Feb 25, 2011
    Which LTM version are you working with? On 10.2.1, there is a send and receive string section for a UDP monitor.

     

     

    Aaron
  • hoolio's avatar
    hoolio
    Icon for Cirrostratus rankCirrostratus
    Feb 25, 2011
    It looks like this was added in 10.2.0 per CR131196. I guess the original logic is that if LTM doesn't get an ICMP port unreachable message, the service is considered to be up. If you want to check the reply you could either use an external monitor with netcat to send a request or upgrade to 10.2.0 or higher (ideally 10.2.1).

     

     

    See SOL6143 for a description of the pre-10.2.0 UDP / ICMP monitor behavior:

     

     

    sol6143: UDP health monitor operation

     

    http://support.f5.com/kb/en-us/solutions/public/6000/100/sol6143.html

     

     

    Aaron