[TriLUG] Re: DNS lookup of Linux server fails intermittently (was: (no subject))

[Geoffrey Douglas Purdy]

ohn,


> > The command to reload the DHCP stuff on Win2k is:
> >     ipconfig /renew

Yes, that's the one.


> > Do you have "KeepAlive" turned On for the server?

I'm not sure.  Which server - the apache webserver, the DNS server, or the
DHCP server?


> > Could the machines be
> > getting new addresses while the browser still thinks it has a good
> > connection?

Again, not sure.  I'm going to guess probably not.  As far as I know,
the leases last three days and the problems seem to occur more
frequently than that.  I'll check with the Win sys admin when he's in on
Mon.

> > Then does simply quitting the browser and
> > restarting fix it?

I don't think so, but I'll need to double check on that one too.  I've
not been able to reproduce this problem on my W2K client so I've
generally been looking over the shoulder of the Win sysadmin on other
people's machines.  I know a cold reboot fixes it, but I'm not sure about
a log off / log on or restarting the browser.

> > Is your server running using Virtual Hosts?
No.  All the VirtualHost stuff is commented out (as by default) in the
httpd.conf file.

> > Is the server name set to the FQDN?
The ServerName directive in httpd.conf is commented out.  The docs
indicate that it should be enabled if the server is to return a FQDN other
than the hostname.  Since the FQDN I would be entering is the same as the
FQDN of the host, I have left this commented out.

The hostname of the linux server is set to the FQDN
(myserver.mydomain.com).


> > What do the error logs for the serve show?
The apache access_log shows nothing doesn't show a record of the
unsuccessful attempts to connect to the server.  Nothing unusual
appears in the error_log.


Thanks for your help.


> > -----Original Message-----
> > From: Jon Carnes [mailto:jonc at nc.rr.com]
> > Sent: Friday, November 30, 2001 5:53 PM
> > To: trilug at trilug.org
> > Subject: Re: [TriLUG] (no subject)
> >
> >
> > The command to reload the DHCP stuff on Win2k is:
> >     ipconfig /renew
> >
> > If that fixes the problem, then I would tend to suspect the
> > DNS and DHCP.
> >
> > ===
> > Do you have "KeepAlive" turned On for the server?  Could the
> > machines be
> > getting new addresses while the browser still thinks it has a good
> > connection?  Then does simply quitting the browser and
> > restarting fix it?
> > Is your server running using Virtual Hosts?  Is the server
> > name set to the
> > FQDN?
> >
> > What do the error logs for the serve show?
> >
> > ----- Original Message -----
> > From: "Geoffrey Douglas Purdy" <gdpurdy at unity.ncsu.edu>
> > To: <trilug at trilug.org>
> > Sent: Friday, November 30, 2001 5:32 PM
> > Subject: [TriLUG] (no subject)
> >
> >
> > >
> > > I've been pulling my hair out over a problem for the last two days
> > > and I'd love some suggestions.  If nothing else, I'd like
> > some reassurance
> > > that my Linux server configuration isn't the source of this problem.
> > >
> > > The problem is as follows.  I've set up a Red Hat Linux 7.1
> > server running
> > > Apache 1.3.22 to serve a website for a private network.  Apache
> > > is running fine -  I can hit the website all day by IP
> > address without
> > > any problem.  The trouble is that when W2K clients running
> > IE6 try to
> > > access the server by its fully qualified domain name (i.e.
> > > http://myserver.mydomain.com) the clients will intermittently get a
> > > "Cannot find server or DNS error" message.  However, client
> > browser can
> > still
> > > access the site by IP address and the client can ping
> > myserver.mydomain.com
> > > successfully.  However, the client browser just can't
> > access the site by
> > > the fully qualified name.  If the W2K client is instructed
> > to reload it's
> > > DHCP information (some command our Windows sys admin issued
> > that I can't
> > > remember), the client browser can then access the Linux
> > webserver by fully
> > > qualified domain name without a problem.
> > >
> > > I thought I had found the problem when I looked in the Network
> > > Configuration -> Names tab on the Linux server and saw the
> > following:
> > >
> > > Hostname: myserver
> > > Domain: mydomain.com
> > > Search for hostnames...:
> > > Nameservers:
> > > <internal DNS server IP here>
> > > <external DNS server IP here>
> > >
> > >
> > > I changed the above to:
> > >
> > > Hostname: myserver.mydomain.com
> > > Domain: mydomain.com
> > > Search for hostnames...:
> > > Nameservers:
> > > <internal DNS server IP here>
> > > <external DNS server IP here>
> > >
> > >
> > > In the Network Configuration -> Hosts tab I left things alone as:
> > >
> > > IP                  Name                   Nicknames
> > > 127.0.0.1           localhost.localdomain  localhost
> > > <IP address here>   myserver.mydomain.com  myserver
> > >
> > >
> > > After making these changes, I restarted the Linux box.
> > >
> > >
> > > I realize that there are many layers that could be the
> > source of this
> > > problem.  The DNS servers and clients are all W2K and are
> > administered
> > > by our Windows sys admin so I know little about such
> > things.  I'd like to
> > > focus on the potential for mis-configuration on the Linux server.
> > >
> > > What are the chances that my Linux server is at fault here?
> > > Does my Network Configuration look reasonable?
> > > Do I need to revisit my apache httpd.conf file?
> > > Any other suggestions where to look?
> > >
> > > Apologies for the verbose message.  Any help will be
> > greatly appreciated.
> > >
> > > Geoff
> > >
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