Summary: DNS again....

From: Larry Chin (
Date: Thu Jan 07 1993 - 13:20:17 CST

> 1) The various manuals allude to dire consequences if the domainname
> is not set with a leading period in ie: ""
> ^
> It seems from the documentation that these dire consequences are
> related to sendmail more than anything related to DNS.
> Can anyone enlighten me on this ? I am a little confused since
> everything seems to be working fine and the domain name does not have
> the leading period.

The following from says it best.

What this refers to is suns sendmail, which relies on NIS, will strip off
the first decriptor in the domain name, i.e. will turn into
com. This creates big problems when people attempt to reply to mail
emanating from your site. A leading '.' or '+' will make it stick so becomes in your return addresses. There are a few reasons
sun wants to do this, speciffically for scalability reasons. They are trying
to enforce inter organization sub decriptors so to simplify your email
delivery system. The only problem is they don't say this.

Addendum: If you have DNS running and have the domain defined in the resolv.conf
file with a "domain" line, this whole issue can be ignored.

>2) If I am running NIS in addition to DNS, do I need to start up the
> in.named on all the client machines. That is does DNS have to be
> running everywhere or just on the NIS master and slaves, since in
> making the NIS maps with the "-b" option inserts the magic cookie
> pointing to DNS lookups.

Everyone seems to agree that if the NIS maps are made with the -b option then
DNS only has to run on the name server master and if desired the slaves. ON
the DNS clients that only thing that is required if resolv.conf and this only
if one wants to do nslookups.

Many thanks to:

Aydin Edguer <edguer@alpha.CES.CWRU.Edu>
David Fetrow <>
Steve Lodin <>
Christian Lawrence <> (Denise Richards) (Jason Thomasser)
tgsmith@spdev.East.Sun.COM (Timothy G. Smith - Special Projects)

Larry Chin {} CCH Canadian Ltd.
System Administrator 6 Garamond Court
Research and Development Don Mills, Ontario.
(416) 441-4001 ext. 349 M3C 1Z5

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