traceroute with 2 interfaces

[derek b smith_1]

All,

I ave two NICS, lan0 primary at 97.5 and lan1 at 99.65. We use the 99 network for our backups but when I do a traceroute to our default router 97.254 it the system (11i on a 8400) it states "Warning multiple interfaces found using 99.65 on lan1."

It should be using lan0, is there a order list in 11i?

thanks, derek

[John Poff · Accepted solution]

Hi,

Have you tried this:

traceroute -i lan1 #.#.97.254

JP

[Steven E. Protter]

Somewhere in /etc/rc.config.d/netconf is an indicator as to which NIC is the primary NIC.

I think its the one that has the default gateway on it.

Take a look at the file, its documented and don't make a backup copy in /etc/rc.config.d/ it will get processed and you will have no netowrking.

SEP

[Mel Burslan]

without knowing what your routing tables look like, it is hard to guess why it was exhibiting such a behavior. Unless ofcourse some genius decided to add/alter the default route to go through the backup interface instead of your main interface, i.e., 97.5 ip addressed one.

if you can provide the information coming out of the follwing commands, it would be much more helpful.

ifconfig lan0 (for 97.5 address interface)
ifconfig lan1 (or lanX for 99.65 interface)
netstat -rn

[RAC_1]

Depending upon how route table looks, it will be routed through primary interface. Which further depends upon /etc/rc.config.d/netconf file.

You may user -i option of traceroute command.

Anil

[Jeff Schussele]

Hi derek,

You can also use the -s xxx.xxx.xxx.xxx to specify just which IP you want the ICMP ping traffice to originate from - as follows:

ping -s source_IP destination_ip

Bottom line is that recent traceroutes will pick a default source I/F for the traffic - which may not be where you'd like - *unless* you override it with -i or -s

HTH,
Jeff

[Marvin Strong]

sound like maybe ip_forwarding is enabled.

[Sridhar Bhaskarla]

Hi Derek,

It's the behaviour for 11i. It will use the first interface found on the system.

You can find the first interface with 'netstat -in' command.

You will need to use either -i option or -s option to direct the traceroute.

-Sri

[Geoff Wild]

There are differences between the traceroute-binaries of 11.00 and 11.11.
The version contained by 11.11 requires the "-i" option if there are multiple interfaces installed on the system.

Rgds...Geoff