Re: 2.2.15 + IPv6: serious bug when removing aliased interfaces

From: Peter T. Breuer (ptb@it.uc3m.es)
Date: Sun May 21 2000 - 10:58:26 EST


"A month of sundays ago Pekka Savola wrote:"
> I just found a serious bug in 2.2.15 (probably also previous versions,
> didn't check) w/ IPv6 and IP Aliasing support compiled in.

This is a "bug" that I've mentioned a few times now. The standard
answer here is that it's meant to be that way, use a 255.255.255.255
netmask in the ifconfig command, use other if tools, ...

> Do the following when networking works fine:
>
> ifconfig eth0:5 1.2.3.4
> ifconfig eth0:5 down
>
> whoops. ifconfig deleted *all* eth0 routes, including the default route.
>
> Also, after that, funnies start to happen (e.g. when trying to add the
> routes back, it says eth0 isn't active or some such).
>
> If I disable IPv6 from the kernel, recompile and reboot, everything works
> just as it should.

Interesting. I alwyas did have ipv6 inserted as a module. Never tried
it without. Yes, downing an alias is fun and games. I have resorted
to realiasing it to something harmless instead.

> Tested on two RH62 boxes, one with ~vanilla 2.2.15, the other w/ redhat's
> 2.2.14-12. Using net-tools 1.55.

(2.2.10 mostly here, and just try it with lo:0).

Peter

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