Not sure if this reply on the previous thread was overlooked due to forum
changes. Problem is basically that when a second dns server is active
servicing the same domain, the workstn still only attempts to contact the
first dns server listed in the Subnet DHCP other options field. Yet this
field will take more than one ip address. Is it supposed to work?

(See below for details).


Steve Law


Hi Brad, thanks for suggestions.

I checked the A and PTR records for both servers, they did have records that
matched the NDS DHCP-DNS server objects i.e. DNS_NWBSOTP04 etc, but not
matching the exact Netware server name. However, putting these in didn't

Nothing happens in the NAMED debug screen when this problem occurs. The
workstation or server simply try to contact the DNS server for a reverse
lookup, can't find the 'default' one and give up.

When we switch from Server1 to Server2 we change all related DHCP and DNS
config settings in the Mgmt Console to Server2, down Server1 and reload the
modules on Server2. However both the workstation and the server insist on
getting IN-ADDR lookup info from Server1.

There are workarounds. On the server, changing the order of the two
NAMESERVER entries in resolv.cfg so that Server2 comes first, then
reinitializing system, makes reverse lookups work on Server2.

For the workstation, if we:
a) change the DHCP Subnet options so only Server2's IP address is listed in
the 'Other DHCP options/Option Name/DNS server' box.
b) reload DHCPSRVR and NAMED on Server2
c) release and renew the IP address on the workstation

....then the workstation reverse lookups work.

Also on the workstation if you run an nslookup in dos and define the server
to use i.e.

nslookup Server2

....that works too. But neither of these is an effective fix. We can't renew
and release the addresses on every single workstation in the building.

The problem is that although the Subnet/Other options/DHCP option defines 2
servers as Domain Name Server (Code 6), the workstation will only try the
first entry. Same for the server's Nameserver entires defined in resolv.cfg.

There are other entries possible in Subnet/Other options/DHCP options, like
'Name Server' (Code 5). Could they be relevant?


Steve Law

"Brad Doster" <bd@NSCSysOps.net> wrote in message
> First thing to check is that you have both A and PTR records for both
> DNS servers. If yes to that, next guess would be to add the first
> (down) DNS server to the second server's sys:etc\hosts file -- at
> least
> it seems that should take care of the "Default DNS server name cannot
> be resolved." error message.
> Also, for additional clues, check the NAMED log files -- on NW 6.5 see
> the command line options for NAMED; below 6.5 use DBGLOG.EXE to record
> NAMED -V output to a file.
> bd
> NSC Volunteer SysOp
> www.InsightNetSolutions.net