Forum Discussion

Andre-Germany's avatar
Andre-Germany
Icon for Nimbostratus rankNimbostratus
May 12, 2015

smtp check

Hello,

 

I have in ltm a smtp check and the pool with the check is down. With tcpdump can´t see pakets to the nodes and in the debug log is whistled "error: couldn't open socket: host is unreachable"

 

Why can´tt I see any packages with tcpdump?

 

When i use a normal TCP check with port 25 is the pool up

 

application delivery
LTM

6 Replies

  • Brad_Parker's avatar
    Brad_Parker
    Icon for Cirrus rankCirrus
    May 12, 2015

    Since the host is unreachable you could have an ARP issue. Meaning, your LTM may not be able to resolve a MAC address for the node you are testing and therefore you are not ever sending a SYN packet to even open the connection.

     

    • Brad_Parker's avatar
      Brad_Parker
      Icon for Cirrus rankCirrus
      May 13, 2015
      can you see packets with tcpdump with your TCP monitor since you say it succeeds?
  • nitass's avatar
    nitass
    Icon for Employee rankEmployee
    May 13, 2015

    can you also post the pool and monitors configuration?

     tmsh list ltm pool (name)
 tmsh list ltm monitor tcp (name)
 tmsh list ltm monitor smtp (name)
  • Andre-Germany's avatar
    Andre-Germany
    Icon for Nimbostratus rankNimbostratus
    May 15, 2015

    ltm pool SMTP-TEST { members { TEST1:smtp { address 1.1.1.1 session monitor-enabled state down } TEST2:smtp { address 1.1.1.2 session monitor-enabled state down } } monitor SMTP-TEST partition Common

     

    ltm monitor smtp SMTP-TEST { debug no defaults-from /Common/smtp description "SMTP TEST" destination *:smtp interval 5 partition Common time-until-up 0 timeout 16

     

    ltm monitor tcp TCP25 { adaptive disabled defaults-from /Common/tcp destination *:smtp interval 5 ip-dscp 0 partition Common time-until-up 0 timeout 16