FreeBSD & FIBs (setfib) - How to modify?

Nikos Vassiliadis nvass9573 at
Thu Jul 16 17:47:31 UTC 2009

Brent Bloxam wrote:
> Nikos Vassiliadis wrote:
>> Brent Bloxam wrote:
>>> The documentation on FIBs is pretty slim unless I've been looking in the
>>> wrong places, all I've seen are a few mentions in errata and release
>>> notes. setfib(1) doesn't offer much in the way of associated commands,
>>> and definitely doesn't explain how to actually work with a FIB. I'm
>>> curious if there's a command to specifically modify a FIB beyond 0,
>>> besides something like
>>> setfib 1 route add ...
>> setfib selects the routing table for locally originated
>> outgoing packets. Besides locally originated packets, there
>> are packets arriving from the network and need to be forwarded.
>> These packets can be classified in a specific routing table
>> with the aid of ipfw. That's all there is. I can't think
>> of something else that needs to be thought with regard to
>> multiple routing tables.
>> HTH, Nikos
> Sorry, perhaps I wasn't clear. What I'm interested in is if there's a 
> way to deal with *modifying* those other routing tables, besides using 
> setfib as I described (e.g., you want to have a different default 
> gateway). There would be no reason to have multiple routing tables if 
> they're carbon copies of one another.

setfib has no internal commands. setfib runs the command you tell it
to in a specific routing table. You modify/inspect the routing tables
with the standard tools, that is route, netstat, some dynamic routing
daemon(quagga, etc) and in general everything that's related to the
routing table.

Just start a shell in FIB 10 and every command forked from
that shell will be bound to FIB 10.
setfib 10 csh
... do some work
you're back in FIB 0.

HTH, Nikos

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