Iproute2: how to fix routing so that traffic to a certain subnet always goes through a certain router?

Question

linux

Hello Toaster. It is required to organize the forwarding of traffic through a specific router. Implemented via ip route add 8.8.8.8 via 88.12.34.1 ; Traffic starts to go along this route, but sometimes for some reason leaves through the default gateway. How to make traffic to 8.8.8.8 always leave and only always through 88.12.34.1?

Answer 1

Traffic starts to go along this route, but sometimes for some reason leaves through the default gateway.

What does "sometimes for some reason it goes away" mean? An IP network is a deterministic system, not ... "sometimes" ;-)
This cannot happen if your interface 88.12.34.1 is up. Or somewhere along the route of this route there are problems (this may also depend on which dynamic, territorial routing system you are included in). See traceroute for how the route is going.

Answer 2

ip rule add help
ip route add default via 88.12.34.1 table <same as when adding rules>
it is important that the rule number is less than that of main. something like this. in theory, with such a rule in the table main will not even look