NLB to F5 migration issue

Hi,

 

We have running application served by NLB The current setup is : internal DNS send internal users to PIX then to applications Vlan 15 which have the gateway on PIX Global DNS send external clients to PIX then to applications Vlan 15

 

We have connected our 2 F5 boxes with external interfaces connected to a new Firewalls and internal to Vlan 15.

 

We tested the F5 internally by modifying users host file and it worked good. Then we published one of the Applications and external clients can access it

 

The problem we faced is that suddenly NLB stopped working for internal users, but still working for external clients. The only change before this issue is that we upgrade F5 to latest release, after roll back to 12.x , the NLB problem solved Second day again NLB stopped working but for all external clients and still working for internal users So all published services weren't working at this time. Shutting down F5, the NLB issue solved

 

At all times F5 is working good when we test it. and NLB can work either from inside or outside as discussed above

 

So I'm asking why F5 is affecting NLB like this. although the traffic path to NLB isn't hitting F5 at all. and NLB was working for internal or external only !

 

I have though for Auto lasthop but I think it affect only outside path to firewalls and routers not the application. But I think to disable this variable for server vlan 15 as a test

 

IS any one met an issue like this when having both F5 and NLB on same network.

 

Our F5 is working as active active with 2 traffic groups

 

Thanks Haithan