[H-GEN] Problems with Linux loopback interface

Martin Pool martinp at mincom.com
Sun Dec 5 21:08:59 EST 1999


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Mark Suter wrote:

> I've run the following from single user mode.
> 
>     # netstat -rn
>     Kernel IP routing table
>     Destination     Gateway         Genmask         Flags   MSS Window  irtt Iface
>     127.0.0.0       0.0.0.0         255.255.255.255 UH        0 0          0 lo
>     # uname -a
>     Linux zwitterion.humbug.org.au 2.2.11 #7 Thu Aug 26 02:41:01 EST 1999 i586 unknown
>     # ping -q -c 510 -f 127.0.0.1
>     PING 127.0.0.1 (127.0.0.1): 56 data bytes
> 
>     --- 127.0.0.1 ping statistics ---
>     1020 packets transmitted, 510 packets received, 50% packet loss
>     round-trip min/avg/max = 0.5/49.2/91.5 ms
> 
> I'm stumped.  How about you?

My next move would be to run ping and traceroute with the (-v ?) option
to show all results: it would be interesting to see if you're getting
ICMPs or errors, or if the packets are just disappearing.  Also try
running strace or tcpdump while running ping for similar reasons.

Try running with SO_DEBUG (-d).  You will need to check the docs to see
where the output from this goes to;  I think it might be kmsg?  This
might be disabled in the kernel.

As robk suggests, you may want to move to 2.2.13.  Alternatively, keep
the same configuration but move to an earlier kernel.  Check through
http://www.kt.opensrc.org/ 

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