Problems with Linux loopback interface

[Mark Suter]

Folks,

I have a weird problem and I need help.  I am experiencing
severe packet loss on the loopback interface, as follows.

    # ifconfig lo
    lo        Link encap:Local Loopback  
	      inet addr:127.0.0.1  Mask:255.0.0.0
	      UP LOOPBACK RUNNING  MTU:3924  Metric:1
	      RX packets:513406 errors:0 dropped:0 overruns:0 frame:0
	      TX packets:513406 errors:0 dropped:0 overruns:0 carrier:0
	      collisions:0 txqueuelen:0 

    # 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 = 0.9/85.7/170.6 ms

For some reason, the number 510 is significant.  If I try any
number of packets from 1 to 510, I get 50% packet loss.  If I
try greater numbers, even 511, I still only receive 510 packets.
When I finally hit <ctrl-C>, I get something like the following.

    # ping -q -c 511 -f 127.0.0.1
    PING 127.0.0.1 (127.0.0.1): 56 data bytes

    --- 127.0.0.1 ping statistics ---
    96204 packets transmitted, 510 packets received, 99% packet loss
    round-trip min/avg/max = 0.9/85.4/170.0 ms

I've included some information about my system below.
Can anyone see a reason for this?  Does anyone get the same
results?  Any suggestions?  Any LARTs?

Yours sincerely,

-- Mark John Suter | I know that you  believe  you understand
suter at humbug.org.au  | what you think I said, but I am not sure
PGP encryption is OK | you realise that what you  heard  is not
Ph: +61 4 1162 2316  | what I meant.                  anonymous

----------------------------- begin -----------------------------
$ wget ftp://ftp.sai.msu.su/pub/Linux/ver_linux
$ sh ./ver_linux

-- Versions installed: (if some fields are empty or looks
-- unusual then possibly you have very old versions)
Linux zwitterion.humbug.org.au 2.2.11 #7 Thu Aug 26 02:41:01 EST 1999 i586 unknown
Kernel modules         found
Gnu C                  2.95.1
Binutils               2.9.5.0.12
Linux C Library        ..
ldd: missing file arguments
Try `ldd --help' for more information.
ls: /usr/lib/libg++.so: No such file or directory
Procps                 1.2.9
Mount                  2.9
Net-tools              (1999-01-01)
Kbd                    0.96
Sh-utils               1.16

$ ls -F1 /lib/libc-*
/lib/libc-2.1.2.so*

$ ldd --version
ldd (GNU libc) 2.1.2
Copyright (C) 1999 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Written by Roland McGrath and Ulrich Drepper.

$ ls -F1 /usr/lib/*c++*
/usr/lib/libstdc++-3-libc6.1-2-2.10.0.a
/usr/lib/libstdc++-libc6.1-2.a.3@
/usr/lib/libstdc++.so.2.7.2@
/usr/lib/libstdc++.so.2.7.2.8*
/usr/lib/libstdc++.so.2.8@
/usr/lib/libstdc++.so.2.8.0*

-----------------------------  end  -----------------------------