[Samba] smbclient segfault with mulicast DNS (mdns) enabled

Andreas Ntaflos daff at dword.org
Thu Mar 16 13:21:59 GMT 2006

Hello list, 

Using Samba-3.0.21c (with these USE flags: cups doc postgres python xml 
xml2) as a standalone server on Gentoo Linux in a small LAN.

I noticed the following: when using mutlicast DNS (mdns, for example to 
make use of zeroconf [1] in a network with Macs and Linux and Windows 
machines) with a resolver like Apple's mDNSResponder, avahi [3] or a 
client like nss-mdns [2] one has to have an mdns entry 
in /etc/nsswitch.conf like this:

	hosts: files mdns dns


	hosts: files mdns4 dns

in order to be able to resolve a .local. domain. 

This seems to disturb Samba severely when trying to resolve NetBIOS 
names. It doesn't matter whether there actually is an mdns daemon 
running, just the presence of the 'mdns' entry in /etc/nsswitch.conf 
causes a segmentation fault when using smbclient, like this:

> smbclient \\\\windows-pc\\share
Segmentation fault
> smbclient \\\\\\share

As you can see the first call segfaults, the second doesn't, apparently 
because nmbd doesn't need to resolve the name.

I'd like to attach a backtrace of the segfault but there seem to be no 
useful debug symbols available for that. I could swear I saw a 
backtrace in one of the Samba log files but I can't seem to find it 

I really don't think smbclient should behave like this, surely this is a 
bug? A known issue? I didn't find it filed on Samba's Bugzilla, should 
I file it? 


[1] http://www.zeroconf.org/
[2] http://0pointer.de/lennart/projects/nss-mdns/#overview
[3] http://avahi.org/
Andreas "daff" Ntaflos 
daff AT dword DOT org
Vienna, Austria 
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