Yep, crappy routers tend to do this :/

fulafel · on April 10, 2014

It's not a real router if it does NAT. NAT is just a half assed proxying hack for hosts not on the internet.

feld · on April 10, 2014

A Juniper MX960 can do NAT. Is that not a router?

fulafel · on April 11, 2014

If it's configured to do NAT instead of routing, then it's not being a router. Routing is a job and "router" describes a role, not a static property of a box. Like firewall, bridge, etc.

Routing is defined as shuffling packets where they need to go unmolested - without messing with the address or port fields. It's specced in the IP RFC's. If you're mangling the traffic, you're violating router requirements.

feld · on April 13, 2014

You're never seen a router have to do NAT for two subnets that it's routing between?

jlgaddis · on April 11, 2014

While I certainly share your dislike of NAT, this is just absurd.