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I went down this road about 15 years ago as the IT person for a small firm. My first pass at it was a linux box with 2 network cards, and 3 addresses (2 public
by mikewarot 3y ago
I went down this road about 15 years ago as the IT person for a small firm. My first pass at it was a linux box with 2 network cards, and 3 addresses (2 public IP addresses on eth0, and a local address on eth1).
Linux only has one routing table, so I had to use ebtables, and ipchains (I think?) to mark packets as they came in, and route them back out correctly. It worked well, but I was worried about the long term stability of it.
Then I found out that SonicWall made a box that did failover automatically, and never looked back.
I strongly suspect there is an open source project which does this these days.
- h2odragon 3y ago> Linux only has one routing table, Not the case for 20 years+. see "TABLE" in `ip route help` and `ip ro ls table all` to see all the route tables you currently have active... you might not have seen the 'local' routes before
- mikewarot 3y agoThat's cool.... the situation we were in was that we had multiple public ip addresses in each of our class C static addresses, but no BGP routing because we were small fry. I used DNS round robin so that from the outside world, it would try either route in, then forward those packets in to the appropriate server. Its good to see you don't have to mark those packets manually any more.
- nazgulsenpai 3y agoOPNsense has configurable multi-wan support. We relied on it pretty heavily at a previous employer where unreliable we were forced to rely on unreliable DSL/cable connections for branch offices. https://docs.opnsense.org/manual/how-tos/multiwan.html https://docs.opnsense.org/manual/how-tos/multiwan.html