Red Hat Bugzilla – Bug 17915
Tracroute does not work with ISDN ippp0 Device over Gateway
Last modified: 2015-03-04 20:08:37 EST
traceroute does not work over an isdn connection /dev/ippp0. After removing
(traceroute-1.4a5-aliases.patch) from the src.rpm it works. It's seems that
there is a
Bug in this patch.
On my system traceroute appears to be sending packets with the source address of
eth0 (192.168.0.1) rather than the public IP address of ippp0, even when told
'-i ippp0' on the command line. Presumably the same bug.
*** Bug 18471 has been marked as a duplicate of this bug. ***
This is also true on my system with standard dialup ppp on 7.0
Looking through the search_routing_table routing and my /proc/net/route file, it
would appear that the code to find the gateway route works fine, but then the
subsequent code to match interface to gateway fails for all point to point
Ie, for a ppp link with local 18.104.22.168 and remote 22.214.171.124, the mask is
Hence if ((al->addr & al->mask) == (use_gateway & al->mask)) is never true,
because use_gateway (the gateway address) is never the same as the local ip
A point-to-point special-case would appear to be in order.
Could you test this with the latest traceroute (-25) from rawhide? It has a big patch (regarding source routing)
which AFAIR touches some issues used here.
Not all point-to-point links; this would appear to work (granted, recompiled for RHL62) just fine for:
ippp0 Link encap:Point-to-Point Protocol
inet addr:126.96.36.199 P-t-P:188.8.131.52 Mask:255.255.255.0
UP POINTOPOINT RUNNING NOARP MTU:1500 Metric:1
But here P-t-P is withing the netmask.
For what it's worth, search_routing_table is not always run when you traceroute. A debugging
printf reveals this. I recall it isn't run unless you use '-s'.
If you are curious, does it this work with stock traceroute-1.4a11 + patch (see #23013).
Can you test with the upgraded package (1.4a12) available at http://www.netcore.fi/pekkas/linux/
(also mentioned on the other isdn traceroute reports) ?
Closing this bug due to inactivity.
Read ya, Phil
A lot of traceroute bugs in RHL7 seem to be the same as this one. 21095, 28367.
I experienced this problem with an updated RHL7 too. It was fixed by installing
RHL7.3's traceroute (traceroute-1.4a12-2.i386.rpm).
I really think that this should be issued as an update for RHL7.0