Re: multihomed linux box - dual t1
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
A long time ago, in a galaxy far, far way, someone said...
>
> hi ya...
>
> think theres lot's of folks with dual t1...
Or dual DSL, or DSL + Cable modem, or dual DSL + Cable modem (like I have
at work).
> for outgoing traffic... think the routing and metrics might work..
Exactly.
> for incoming traffic... we'd need all kidns of whacky work arounds
> or an autonmous ip# routable by either isp...
No workarounds. Policy routing :)
Like so:
Environment:
eth0: 192.168.1.2/24; gateway 192.168.1.1
eth1: 10.0.0.2/24; gateway 10.0.0.1
Special magic:
ip rule add from 192.168.1.2 lookup 1
ip rule add from 10.0.0.2 lookup 2
ip route add to default via 10.0.0.1 metric 0
ip route add to default via 192.168.1.1 metric 1
ip route add table 1 to 192.168.1.0/24 via eth0
ip route add table 1 to 10.0.0.2/24 via eth1
ip route add table 1 to default via 192.168.1.1
ip route add table 2 to 192.168.1.0/24 via eth0
ip route add table 2 to 10.0.0.2/24 via eth1
ip route add table 2 to default via 10.0.0.2
This all assumes that the Linux box is alone it's little world, without
some sort of Masquerading going on. More magical incantations are needed
if there is.
The "ip ..." lines work with both the 2.2.x and 2.4.x kernels.
And yes, an IP number space routable by more than 1 ISP will work to :)
> - who's writing this howto ???
A number of people involved in the development of Linux's networking
abilities.
The web page for it is at http://ds9a.nl/2.4Routing/; I know it says 2.4
in the link but experience tells me that alot of it works with 2.2.x.
> -- UUnet also has a backup "dark t1" that they provide ...for a minimal
> fee ... so that even if the primary t1 goes dow... you have a backup
> and the world does not know about your fiber being cut by the
> bozo and his backhoe down the street
You still need a method to tell the world to use that T1... like BGP.
> - not sure if the same ISP can be up if their other wire went
> down... ( or router or hubb or 110v power etc )
If the T1 goes through the same ISP I think you've lost a good portion of
your redundancy...
> - pacbell ( SF bay area ) had a major fiber ring outage about a month
> ago.... where the main fiber was cut late one afternoon ...
Exactly for this reason :)
- --
- ----------------------------------------------------------------------
Phil Brutsche pbrutsch@tux.creighton.edu
GPG fingerprint: 9BF9 D84C 37D0 4FA7 1F2D 7E5E FD94 D264 50DE 1CFC
GPG key id: 50DE1CFC
GPG public key: http://tux.creighton.edu/~pbrutsch/gpg-public-key.asc
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.0.6 (GNU/Linux)
Comment: Made with pgp4pine
iD8DBQE7SnIV/ZTSZFDeHPwRAhfkAKCKHjSpsIBWTf+5E7Ty8QsbQnn+0ACeL0/b
p1EeqUUHkGcC+Jjc55Xx7zM=
=p3zL
-----END PGP SIGNATURE-----
Reply to: