[pkg-lighttpd] Bug#564556: lighttpd: can't bind to port: :: 80 Address already in use

[Jonathan Nieder]

Package: lighttpd
Version: 1.4.25-2
Severity: minor

lighttpd refuses to install, seemingly because it is trying to bind
to port 80 twice:

| Setting up lighttpd (1.4.25-2) ...
| Starting web server: lighttpd2010-01-10 00:57:30: (network.c.345) can't bind to port: :: 80 Address already in use 
|  failed!

Invoking the init script by hand yields the same result:

| # /etc/init.d/lighttpd restart
| Stopping web server: lighttpd.
| Starting web server: lighttpd2010-01-10 01:24:05: (network.c.345) can't bind to port: :: 80 Address already in use 
|  failed!
| # echo $?
| 1

I do not have any other web server installed, nor is any other
program listening on port 80.

| $ netstat -a | awk '($1 != "unix") && ($6 == "LISTEN")'
| tcp        0      0 *:ssh                   *:*                     LISTEN     
| tcp        0      0 localhost:smtp          *:*                     LISTEN     
| tcp6       0      0 [::]:ssh                [::]:*                  LISTEN     

The problem is that (why? I don't know, but that's a separate problem)
the bindv6only sysctl is not enabled.  Enabling it fixes this.

A clearer error message would have made this easier to diagnose.
Even better, lighttpd could set the IPV6_V6ONLY option itself
and not rely on net.ipv6.bindv6only being set.

Thoughts?
Jonathan