IP Route RTNETLINK Error: File Exists

by Scott Wayt » Wed, 31 May 2000 04:00:00

Here's the setup:

The Linux Box has 2 NIC's eth0:External and eth1:Internal, it also has an
aliased IP on eth0:1

I am attempting to use NAT to forward the IP on eth0:1 to an internal IP
address using the following:

ip route add nat 24.x.x.x via 192.168.1.x

Every time I try this I get the following:

RTNETLINK error: file exists

I have also tried forwarding the IP on eth0 and got the same error.

Any help would be greatly appreciated.

What I am trying to do is forward one of our external IP's to an internal
Web box.
It already works if I use IPMasq forwarding for the http port, but
unfortunately we also want to be able to get to this site from inside as
well, thus the NAT solution.

Thanks

Top

1. rtnetlink: network unreachable for Routing for multiple uplinks using ip route add

Dear all,
after playing around and having the same problems on all linux
versions I have at hand and not finding a solution in the net I ask
for your help.

Problem: Want to set up a router with multiple uplinks to the
internet.
Checked documentation at several places, but all examples given will
not work!
Always get rtnetlink: network is unreachable.

Have tried this with IPCop 1.4.5, SUSE Prof. 9.1 same effect.

OK now the details:

For ISP 1 (all IP addresses not the real ones!)
eth0: 10.138.233.227
NETMASK: 255.255.255.240
GW: 10.138.233.226

For ISP2
eth1 10.51.238.226
NETMASK: 255.255.255.240
GW: 10.51.238.226

/etc/rt_tables: (added at end)
200 T1
201 T2

Routing table empty but loopback device when I start:
ip route add 10.138.233.224/28 dev eth0 src 10.138.233.227 table T1
ip route add default via 10.138.233.226 table T1
Error Message: rtnetlink: network is unreachable

ip route add 10.51.238.224/28 dev eth1 src 10.51.238.226 table T2
ip route add default via 10.51.238.225 table T2
Error Message: rtnetlink: network is unreachable

If I use the commands without the table T1/T2 I am able to set the
route. But later it doesn't work.
I took the commands from
Linux Advanced Routing & Traffic Control HOWTO
Chapter 4.2
And crosschecked with
Redundant Internet Connections Using Linux from
http://www.samag.com/documents/s=1824/sam0201h/0201h.htm

Same effect.
Kernel on Suse9.1: 2.6.4-52
Kernel on IPCop: 2.4.29

Kernel configured with:
CONFIG_IP_ADVANCED_ROUTER=y
CONFIG_IP_MULTIPLE_TABLES=y
CONFIG_IP_ROUTE_MULTIPATH=y

ip version:
Suse: iproute2-ss020116
ipcop: iproute2-ss010824

Any clues?

Thanks in advance
Joerg

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