[TriLUG] Conflicting Default Gateways

Michael Thompson thompson at easternrad.com
Mon Aug 16 11:36:33 EDT 2004


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

I don't believe you can have 2 default gateways, even with 2 network
cards.  The only way to achieve your goal is to use some kind of routing
protocol that would know if one gateway was down and automatically use
the other, or policy routing (if destination is <foo> then route through
gateway <bar>)...

$.02

- --mike

Brian Henning wrote:
| Hi List,
|   Ok, I think I have a foggy idea of why this is the case, but I would
| greatly appreciate some tips on how to get around it:
|
| I've got a server with two NICs which are on different subnets (for
| argument's sake, we'll say eth0 is on 192.168.50.0/24 and eth1 is on
| 192.168.100.0/24).  Both subnets have their own internet gateways; .50 has
| 1.5Mbit DSL service, and .100 has some sort of cable-based service.  Right
| now, eth0 is configured to its subnet's default gateway (.50.1), and
eth1 is
| configured with no default gateway.  In this configuration, things work
| normally.  However, if I configure eth1 to be aware of its default gateway
| (.100.1), something becomes amiss, and things such as host and dig get
| broken.  I'm using system-config-network to make these settings; I don't
| know if that matters.
|
| Ordinarily, I simply wouldn't care.  The server does all its dirty
work via
| eth0 anyhow.  The problem is, I would like to have it download large files
| (such as the FC3 ISOs) using eth1, so that the DSL bandwidth isn't hogged.
| I don't care about maxing out the cable bandwidth, because no one uses it
| (it's only there as a failsafe in case the DSL goes down); but
everyone uses
| the DSL so I'd have to do something like only download overnight, or
| rate-limit, neither of which is a solution I am patient enough to persue.
|
| So, is there a way to achieve this?  It seems like I should just be
able to
| configure each interface's default gateway and tell the ftp client to bind
| to eth1, but as I've explained, attempting to have both interfaces'
default
| gateways configured seems to result in some kind of conflict.
|
| Thanks for all the help!
|
| Cheers,
| ~Brian
|
| ----------------
| Brian A. Henning
| Strutmasters.com
| 866.597.2397
| ----------------
|
|

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.2.4 (Darwin)

iD8DBQFBINR+uxlRkoWKZoMRArcSAJ9GKx0h/jqZo271o52NwcSlcQXGUACgiI9G
iY3akYqAJ5ugRzIloZon4Vs=
=Etsx
-----END PGP SIGNATURE-----




More information about the TriLUG mailing list