Disabling IPv6 on *one* network interface in Debian

Bjørn Mork bjorn at mork.no
Tue Feb 15 11:47:54 CET 2011

"Frank Bulk - iName.com" <frnkblk at iname.com> writes:

> After a server reboot this morning I did see link-local recreated, not being
> wiped out by "post-up ip -6 addr flush eth0.100".  I've added a "up ip -6
> addr flush eth0.100" and will see if that makes a difference in the future.

That's very unlikely to make any difference. "post-up" is an alias for
"up", just as "pre-down" is an aliase for "down".

>From ifupdown-0.6.10/ifupdown.nw:


Dealing with the per-interface options is the next thing to deal

<<process iface option line>>=
<<convert [[post-up]] and [[pre-down]] aliases to [[up]] and [[down]]>>
<<check for duplicate options>>
<<add option>>

<<convert [[post-up]] and [[pre-down]] aliases to [[up]] and [[down]]>>=
if (strcmp(firstword, "post-up") == 0) {
        strcpy(firstword, "up");
if (strcmp(firstword, "pre-down") == 0) {
        strcpy(firstword, "down");

This is also documented in interfaces(5) if you don't want to read the


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