network loopback doesn't work in 2.2.1?

Marc Lehmann (pcg@goof.com)
Sat, 30 Jan 1999 18:45:40 +0100


After booting 2.2.1, I found that, although the loopback interface was
up, no route was pointing to it, and "telnet 127.1" didn't connect but
eventually timed out.

eth0, though, was up, had a route and was working.

I then tried to add a route by hand:
route add -net 127.0.0.0/8 dev lo

netstat -r:

127.0.0.0 * 255.0.0.0 U 0 0 0 lo

yet I still couldn't connect to anything. ifconfig showed that lo did indeed
transmit and receive packets:

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:10 errors:0 dropped:0 overruns:0 frame:0
TX packets:10 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0

And my firewall rules also showed that the apckets were accepted:
10 1060 ACCEPT all ------ 0xFF 0x00 * 127.0.0.0/8 0.0.0.0/0 n/a

Booting into 2.1.132 and everything was working fine again (I'm now
running 2.1.132). BTW, I upgraded to net-tools-1.50 at the same time as
I upgraded to 2.2.1, so it might be some kind of synergy effect (But the
same net-tools work under 2.1.32). It also worked with 2.2.0.

Also, I minor note on Documentation/Changes, I can read there:

> Also note that some routes, such as loopback routes, do not show up
>in some standard tools. Check in /proc/net/rt_local to verify their
>presence.

At least on my system there is no "rt_local" file anywhere in /proc.

HTH,

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