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htkiet_42906's avatar
htkiet_42906
Icon for Nimbostratus rankNimbostratus
Oct 22, 2012

Suddently can't ping or access to VS IP add other subnet

Hi all,

 

Can someone let me know if you have been facing this issue?

 

Suddently I can't ping or use web browser to access to the IP add of Virtual Server from other subnet but I can do it if I stand in the same subnet. Then I tried to change the IP add of VS to another one, it is OK to access. Then I changed back to the previous IP add. It is OK. I dont know why this happen.

 

I appreciate if someone can share me about this.

 

 

Thanks,

 

Kiet

 

config
design

14 Replies

  • nitass's avatar
    nitass
    Icon for Employee rankEmployee
    Oct 22, 2012
    do you know whether traffic reached bigip while it was not working (e.g. checking by tcpdump on bigip)?
  • htkiet_42906's avatar
    htkiet_42906
    Icon for Nimbostratus rankNimbostratus
    Oct 22, 2012

    Hi Nitass,

     

     

    Thank you for your reply!

     

    I didn't use check for tcpdump at that time so I don't know if traffic reached bigip or not. Can you let me know two cases:

     

    1. What is the problem if traffic was reaching bigip at that time?

     

    2. What is the problem if traffic wasn't reaching bigip at that time?

     

    BTW, 1, I can use to manage f5 from another subnet at that time (selfIP address is in the same subnet of Virtual IP address. 2, I can from the client in the same subnet.

     

     

    Best regards,

     

    Kiet

     

  • nitass's avatar
    nitass
    Icon for Employee rankEmployee
    Oct 22, 2012
    without the data it is difficult to say. we can guess but we do not know what wrong is indeed.
  • patrickdaj_7040's avatar
    patrickdaj_7040
    Icon for Nimbostratus rankNimbostratus
    Oct 22, 2012

    If it happens again you might also check the ARP cache on the LTMs default gateway. Sounds a lot like a bad ARP entry there.

     

  • htkiet_42906's avatar
    htkiet_42906
    Icon for Nimbostratus rankNimbostratus
    Oct 22, 2012
    Thanks nitass!

     

    Hi patrickdaj,

     

     

    Thank you!

     

    I think maybe this is an reason. Can you please tell me why this happened and how we can fix it.

     

     

    Best regards,

     

    Kiet
  • patrickdaj_7040's avatar
    patrickdaj_7040
    Icon for Nimbostratus rankNimbostratus
    Oct 22, 2012
    Well I think there are a few things suggested that you can do at this point "if" it happens again.

     

     

    1. run tcpdump from bigip to see if traffic is getting there

     

    2. if traffic is not getting to bigip, check arp cache on ltms default gateway

     

     

    There is nothing to be done or fixed though since these are just guesses as to what is happening.
  • htkiet_42906's avatar
    htkiet_42906
    Icon for Nimbostratus rankNimbostratus
    Oct 23, 2012

    Thanks so much Patrickdaj!

     

    I will do as your suggestion when it happens again.

     

    Kiet

     

  • htkiet_42906's avatar
    htkiet_42906
    Icon for Nimbostratus rankNimbostratus
    Oct 24, 2012
    Hi Techgeeeg,

     

     

    Thank you for your message!

     

    Temporarily It is working well, that issue hasn't happened.

     

    I will get back to you if it happens again

     

     

    Best regards,

     

    Kiet