On Tue, 2004-04-20 at 13:12, Niall O Broin wrote:
> We have two servers which are hosted in a colo facility. One (A) is currently
> the primary mail server for a number of domains. I want to make the other (B)
> the secondary server for these domains. Both servers have two LAN
> connections, the second being used for an RFC1918 private network. I would
> like to figure out a way of getting traffic to go from server A to server B
> over the private LAN so that email which lands on B (which will be mostly
> spam, sadly) and is thence forwarded to A travels over the private LAN (where
> bandwidth is not chargeable). Is there any way of doing this, given that the
> public addresses of A are not bound to the private network's NIC?
You could try the following..
Given hosts A and B as follows
public address a.a.a.a on dev eth0
private address x.x.x.x on dev eth1
public address b.b.b.b on dev eth0
private address x.x.x.y on dev eth1
On host A:
route add -host b.b.b.b gw x.x.x.y dev eth1
On host B:
route add -host a.a.a.a gw x.x.x.x dev eth1
You didn't say whether the two public IPs are on the same network. If
this is the case, I think you'll need to change the metrics so that the
route over the private network takes preference, but I can't really
comment on this, not having done it.
John Reilly <jr at inconspicuous.org>
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