[avahi] avahi not functioning on Slackware 12.2

[Ted Percival]

The two most common problems are:
1. Firewall blocking UDP port 5353
2. Network driver doesn't support multicast properly

It sounds like you're running all these commands on the same machine,
can you confirm or deny that?

Anyway run `iptables -L` to see if there are firewall rules blocking UDP
port 5353. Perhaps this was also suggested on IRC.

For #2 (network driver problem) you can test it by running
  ifconfig eth0 promisc
and if it starts working at that point then it would be a bug in the
network interface driver's processing of multicast packets.


Steve wrote:
> (Ha ha, maybe I'll get the list mailing address right this time...)
> 
> Hello!  I apologise if you've seen me ask the same question in the avahi
> irc channel, but I'm still stuck and hopefully someone here could help me
> out.  I'll try to give as much information as possible.
> 
> Most likely this isn't a problem with avahi itself, but since I'm not too
> familar with avahi's internals, I thought I'd ask here.
> 
> On Slackware 12.1, avahi-0.6.22 through to avahi-0.6.24 work fine, and as
> expected.
> 
> However, on Slackware 12.2, I can't browse any services, and it seems I
> can't resolve any .local hostnames.  Running with --debug, the
> avahi-daemon starts up fine, loads services for sftp, and waits; syslog
> reports that the daemon has picked up the new interface and registers it;
> but when I use avahi-discover, it's empty; avahi-browse seems to hang
> waiting for a response, as does avahi-resolve-*.
> 
> Since 0.6.24 works fine with Slackware 12.1, I'm trying to track down what
> has changed which prevents avahi from working on 12.2. (And it's not just
> me, I've had a few other people try avahi-0.6.24 on a fresh Slack 12.2
> install, with the same result as me. :)
> 
> computy.local is the host/server machine. multicast is on.
> 
> 
> Using avahi-resolve-host-name, the avahi-daemon reports:
> 
> dbus-protocol.c: interface=org.freedesktop.Avahi.Server, path=/,
> member=GetAPIVersion
> dbus-protocol.c: interface=org.freedesktop.Avahi.Server, path=/,
> member=GetState
> dbus-protocol.c: interface=org.freedesktop.Avahi.Server, path=/,
> member=GetVersionString
> dbus-protocol.c: interface=org.freedesktop.Avahi.Server, path=/,
> member=GetHostNameFqdn
> dbus-protocol.c: interface=org.freedesktop.Avahi.Server, path=/,
> member=HostNameResolverNew
> 
> But no response is given, and avahi-resolve-host-name continues to wait.
> 
> Strangely (or not strangely), a `dig` to avahi returns an IP:
> 
> $ dig -p 5353 @224.0.0.251 computy.local
> <snip>
> ;; QUESTION SECTION:
> ;computy.local.                 IN      A
> ;; ANSWER SECTION:
> computy.local.          10      IN      A       192.168.2.3
> 
> If i use tcpdump to see what's going on when I run
> avahi-resolve-host-name, I get:
> 
> 20:29:21.804711 IP 192.168.2.3.5353 > 224.0.0.251.5353: 0 [2q] A (QM)?
> computy.local. AAAA (QM)? computy.local. (37)
> 20:29:21.804995 IP 192.168.2.3.5353 > 224.0.0.251.5353: 0*- [0q] 2/0/0
> (Cache flush) AAAA[|domain]
> 20:29:22.812708 IP 192.168.2.3.5353 > 224.0.0.251.5353: 0 [2a] [2q] A
> (QM)? computy.local. AAAA (QM)? computy.local. (81)
> 
> Etc, and it doesn't seem like an IP is returned.  I've tried looking
> through some of the documentation, and poked around on the lists, but i
> can't seem to find any hints.
> 
> Could this be a dbus problem?
> 
> When i start the avahi-daemon with the --debug, i get:
> 
> dbus-service-browser.c: interface=org.freedesktop.DBus.Introspectable,
> path=/Client1/ServiceBrowser1, member=Introspect
> chroot.c: chroot() helper got command 08
> <snip>
> 
> Etc, etc. But this may be a different matter?, and even with --no-chroot,
> it still does not work.  I've tried downgrading the dbus package on
> Slackware 12.2 to that of Slackware 12.1, but it did not help.
> 
> Any suggestions as to what else may be causing this strange problem?  Any
> help appreciated!  :)
>