Be Careful With nisdomainname

[Kurt Wall]

I was working on my book this morning, specifically, configuring an NIS 
client. So, in a classic blunder, used the nisdomainname command to set 
the NIS domain name on my "client" system, which just happened to be my 
mail server. This totally confused Postfix, which couldn't find the 
alias database and accordingly, refused to deliver mail locally:

Out: 250 Ok
 In:  RCPT To:<webdude at kurtwerks.com>
 Out: 451 <webdude at kurtwerks.com>: Temporary lookup failure
 In:  DATA
 Out: 554 Error: no valid recipients

So, after resetting the domain name:

# nisdomainname ''

The mail queue cleared. Oops. ;-)

Note to self: Don't set an NIS domain name on a pretend client that also 
happens to be your domain's mail server. 

Kurt