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redhat 5.2 traceroute concerns

akaltz
akaltz asked
on
Hello,
I have a machine with Red Hat 5.2 that is multi-homed on several different networks. My question is
regarding the traceroute command. Even if you specify an interface using -i, it stills seems to pick
a randomly select interaface to send packets out. Has anybody experienced this before or know of a
traceroute patch or command that I may not be previewed to? I am trying to troubleshoot a routing issue
on this is making it a bit difficult. Also, if you are aware of a site or doc that can provide information
on how Linux (or unix in general) supports networking on multi-homed machines so I can re-check my understanding
that would be great as well.

Thanks
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Commented:
how do you check which interface it uses?
traceroute uses the interface which needs to be used according to the routing table, usually.
Sorry I don't have RH's traceroute, but mine does not have the -i option.

Author

Commented:
I check which interface to use by looking at the route table.  The -i option specifies the interface you want to send traceroute out of for the test.  For example, if I traceroute to a public address and specify the address it is suppose to go to, it says there are multiple interfaces then uses an interface for a private address, not taking into account the route table.
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Commented:
ok, you say that for example
   traceroute -i eth0
does not use the IP of eth0 (which it should according to the man-page). Have you tried:
   traceroute -s aa.bb.cc.dd
where aa.bb.cc.dd is the IP you want to use as the source?

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