Learn F5 Technologies, Get Answers & Share Community Solutions Join DevCentral

Filter by:
  • Solution
  • Technology

Port reuse conflicts with TCP preserve: is there a workaround?

We're having some port reuse issues on an app: we've got the TCP profile set to preserve (not strict) which apparently lets LTM reuse a port while it's still in TIME_WAIT... our Cisco firewall with sysopt timewait (relaxed close) silently drops the SYNs since it's still in TIME_WAIT too.

First off, it seems like that it shouldn't reuse a port in TIME_WAIT unless it was "preserve strict". The not-strict setting sounds like "preserve the port if that's reasonable" and being in TIME_WAIT seems like it should be out of consideration.

Second, is there something I can do in an iRule to address this situation? I see some posts about the timewait table but they're all admin-ish lookups, not real-time adjustments. Is there some way to avoid the port reuse conflict? Or detect it and try a different port? Thoughts?

Thanks - Al

Rate this Question

Answers to this Question