Forum Discussion

TiagoBecker_255's avatar
TiagoBecker_255
Icon for Nimbostratus rankNimbostratus
Mar 24, 2016

GTM/LTM persistence error.

Hi all, this is my first post here, been following the forum for a good while now.

 

As so, the first question already seems to be a tricky one (I searched for this but failed to find anything).

 

I have a 3dns pointing to 2 bigip instances. The 3dns has source address persistance. Bigip uses cookie persistance.

 

The 2 bigip instances are geographically separated. behind every bigip instance, I have a few servers.

 

The problem is, users are being redirected from one bigip instance to the other, even withing the allowed ttl (1800 seconds).

 

Either because they can "get out" through different proxies (external IPs will be different - just an assumption) or for some other reason, not entirely sure. I noticed the cookie is set to session too, without expiration date and even so, we end up with cookies for both bigip instances.

 

Can someone please provide some advice or just point me to where I should be searching for the answer?

 

I'm still learning this, so any help is appreciated.

 

Thanks a lot in advance!

 

application delivery
BIG-IP
LTM

1 Reply

Sort By
  • IanB's avatar
    IanB
    Icon for Employee rankEmployee
    Apr 01, 2016

    When you say 3DNS, are you actually referring to GTM (or BigIP DNS), or are you still running version 4 code ?

     

    The clients are going to make DNS requests to the GTM for the IP address of the virtual they need to connect to. There's persistence that can be applied to the WideIP pool settings, but what that's doing is persisting the same answer back to the same local DNS server. If you clients are making DNS requests that are hitting the GTM from more than one local DNS server, then they could be given different results.

     

    The cookie persistence doesn't really come into it - that's only going to be presented to the pool member once the data centre (the wideip name resolution) has already been selected.