Two ISP – how to configure outbound traffic.

v9 has nice debugging mechanism called iRules. :-)

 

I wrote simple rule to log packet IPs, ports and next/last hops

 

Log shows, in case 3 LTM choose gateway absolutely randomly (or should I say “round robin”?)

 

 

The only way to make it work is to use very same iRules to assign appropriate gateway.

 

With iRules everything works just fine, but it’s somewhat impractical as there is no way to script them - at least I don’t know how.

 

 

Back to original problem:

 

Default gateway pool with 2 gateways doesn’t work at all.

 

I guess, it should – there is no big deal to compare SNATed IP with available gateways and choose the right one.

 

The one difference between my config and average Joe – subnet B is /26 and A is /24

 

Anyway, SNATed IP and gateway both belong to the same subnet – even iRules won’t help otherwise…

 

 

The good thing about it – it made me learn a little bit of iRules ;-)