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neil_t_66364's avatar
neil_t_66364
Icon for Nimbostratus rankNimbostratus
Jan 06, 2015

Static route question when the same IP can be either client or server and accessable through outside or inside interface

Hi,

 

I'd be very grateful for some advice on a routing question. our setup uses an outside and an inside interface and all connections use SNATs. In scenario 1 when 10.0.0.1 is the client it connects to the VIP through the outside interface. in scenario 2 the same IP address is the server and it's accessed via a SNAT through the inside interface. My question is if I have a static route configured for scenario 2 this destination is accessed through the inside interface, will this affect the first scenario when the IP is the client and sits on the outside interface, i.e. will I have asymmetric routing or will the client/VIP-destination/SNAT ensure the static route does not affect the connection? Both client and destination IPs are a layer 3 hop away. As this is a new deployment we are able to make any configuration/design changes.

 

Thanks in advance

 

application delivery
deployment
LTM

3 Replies

  • James_Thomson_0's avatar
    James_Thomson_0
    Historic F5 Account
    Jan 06, 2015

    A few questions: When you say outside and inside interface, do you mean outside and inside vlan? Can you give an example of what the self IP's are on those vlans? When you say in Scenario 2, that the "same ip is accessed via a SNAT through the inside interface" what type of SNAT and what does that configuration look like. Then, the route you're talking about adding? Is that a route for the BIG-IP to learn how to get to the 10.0.0.1 machine?

     

    Making some guesses, if so, the auto-lasthop feature should override your static route so that route should not affect the inbound connection. The BIG-IP will send the packet back to the client the way it came in.

     

  • neil_t_66364's avatar
    neil_t_66364
    Icon for Nimbostratus rankNimbostratus
    Jan 07, 2015

    Thankyou both for your quick replies. I was wondering if there was a auto-last-hop type function as the inbound connection is to a VIP so I guessed there would be some kind of mapping table. @James this is a new setup so there's currently no configuration in place we've just mapped out what needs to be configured. I have seceral years experience with load balancers but only just recently started with F5s. Thanks again to you both