Comment on Weird (to me) networking issue - can you help?
teslasaur@lemmy.world 4 months ago
My guess is that the server receives the packet from the client with src .11.101 dst .10.102 and tries to respond over the interface that has .11.102 assigned. The client expects a response from src .10.102 and drops the packet. But I would turn on a packet sniffer in the gateway to see if the returning traffic even passes the Firewall in scenario 1.
talkingpumpkin@lemmy.world 4 months ago
So the request goes trough but the replies are discarded ? That could actually be it!
I think there was an option to allow martian packets… I’ll search it and give it a try. Thanks!
teslasaur@lemmy.world 4 months ago
It has to do with link priority on the server. You’d imagine that a server that receives a packet that has a return address on the same subnet as it self logically would use that interface instead.
A similar thing happens in switches. For example if you have two vlans on a switch and both vlans have an ip assigned, connect a computer to one of the vlans. You will only be able to reach the switch on the non-routed connection. Even if you also are allowed to reach the second vlan through a router/Firewall.