Asymmetrical Routing

[dm25]

Question for everyone.

I perform a ping with IP Options (Record) from a WAN router located across town, to the data center that I am located at.  This is all private, no ISP's involved.  The return traffic comes back the same physical path, however the return traffic comes back across different layer 3 IP addresses.  Make sense?

Question - Is this an issue?  I am thinking not and that as long as the physical path is the same I am ok.

Thanks

[Jon Marshall · Accepted solution]

It would be different IP addresses because the ingress interface at each device is different on the way to the DC and the way back.

Unless you mean something else.

Even if it took a different physical path it is not necessarily an issue although there can sometimes be issues with packets arriving out of order.

The main issue with asymmetric routing is if you have device that needs to keep state of the connection in the path and it does not see both parts of the connection ie. inbound and outbound. A stateful firewall is a good example and asymmetric routing can lead to it dropping packets.

Jon

[dm25]

That is what I meant.  Thanks for that explanation.