SAMBA digest 1980

Paul Sherwin psherwin at
Fri Feb 12 14:26:43 GMT 1999

At 03:39 12/02/99 +1100, you wrote:
>From: "Daryl L. Biberdorf" <darylb at>
>We're having an interesting problem at our
>I'm wondering if an outage between
>us and the DNS would result in this kind of failure.

Linux sockets seem to react badly to DNS problems - an inability to resolve
a name causes the socket opening to hang for about 2 minutes before
continuing. I haven't worked out why this is yet - I just disabled DNS
resolution altogether (my system isn't part of the 'real' internet). If
your DNS is screwed up lots of TCP/IP stuff will break as well as Samba. A
good test is to telnet to the Linux box from a computer that isn't in the
hosts file - if the connection attempt hangs for a couple of minutes before
giving you a login prompt, DNS is stuffed. smbclient -L SERVERNAME will
also (probably) hang, while smbclient -L SERVER-IP-ADDRESS will work

I also had unrelated but superficially similar problems with keepalive
packets - these weren't being sent by default so when a workstation
rebooted Samba didn't always see it and netbios name resolution broke. If
this happens you'll be able to see the server (sometimes) but not its
shares (sometimes). Enable 'socket options = SO_KEEPALIVE' and 'keep alive
= 60' in smb.conf to fix this.

If you figure out a way to make Linux time out faster when DNS is broken
I'd appreciate an email!

Best regards, Paul

Paul Sherwin Consulting
22 Monmouth Road, Oxford OX1 4TD, UK
Phone +44 (0)1865 721438
Fax +44 (0)1865 434331
Pager +44 (0)7666 797228

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