Re: Traffic NOT moving through the correct network interface?



rout
"Moe Trin" <ibuprofin@xxxxxxxxxxxxxxxxxxxxxx> wrote in message
news:slrnfodevd.m7q.ibuprofin@xxxxxxxxxxxxxxxxxxxx
On Thu, 10 Jan 2008, in the Usenet newsgroup alt.os.linux, in article
<oFjhj.37168$EA5.19884@pd7urf2no>, Calab wrote:

Machine is running Debian 4.0r1 2.6.22-3-686. This machine has three
network
connections.

and the key is in the routing table (/sbin/route -n).

ROOT:~#route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use
Iface
10.0.11.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
68.145.52.0 0.0.0.0 255.255.252.0 U 0 0 0 eth1
68.145.56.0 0.0.0.0 255.255.252.0 U 0 0 0 eth2
239.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 eth0
0.0.0.0 68.145.52.1 0.0.0.0 UG 0 0 0 eth1
0.0.0.0 68.145.56.1 0.0.0.0 UG 0 0 0 eth2
0.0.0.0 10.0.11.1 0.0.0.0 UG 0 0 0 eth0


eth0:
- static IP of 10.0.11.16 with a mask of 255.255.255.0
- connected to a router, which is connected to the rest of my LAN and a
cable modem #1

This ALONE would be OK

eth1:
- dynamic IP
- connected directly to cable modem #2

and you probably expect this to lead to the world - why bother, when
eth0 already fulfills that need.

eth2:
- dynamic IP
- connected directly to cable modem #1

And why should the kernel use this in preference to eth0?

Because the connections on eth1 and eth2 are INBOUND.

eth0 is a gigabit ethernet connection to my LAN. It is used for file access
within the LAN and any incidental (unplanned) outbound internet traffic such
as package retrieval, etc.

eth2 is USB to cable modem #1. This is the inbound connection used for
services accessible from the internet - web, ssh, ftp, etc. I'd expect any
inbound connections to automatically use this port for the corresponding
outbound traffic. This is the least used interface as far as bandwidth is
concerned.

eth1 is 100mb to cable modem #2. This is for the planned, high bandwidth
applications on my Linux PC. bittorrent client, large file transfers, etc.
Applications are specifically bound to this interface in their configuration
files.

At this point, all outbound traffic is going over eth0 regardless of where
the connection originated. bittorrent connections come in eth1, and go out
eth0. Same with SSH and FTP connections.

See the Adv-Routing-HOWTO which should be on your system. Any time
you have more than one route that will take you "someplace", the kernel
will choose the one with the lowest metric - and if the metric is equal,
will choose the last one configured.

I've pasted the results from ifconfig below.

Your munging makes the ifconfig information completely useless.

All three interfaces are on seperate subnets... Shouldn't make a difference
if the IP's are actually real.

WHAT is going on here? Can someone point me in the right direction as
far as troubleshooting this?

-rw-rw-r-- 1 gferg ldp 297491 Sep 4 2003 Adv-Routing-HOWTO

Person who set up the routing doesn't understand the way networking uses
the word "default" meaning as when NOTHING ELSE applies, use this. You
have three defaults - which one to use?

I assumed that outbound connections would pass through the same interface as
the inbound connection that spawned them.

I'll read over the HOWTO... I appreciate the help!


.



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