Postfix: phantom hostname.

Bill Freeman f at ke1g.mv.com
Tue Jun 21 14:06:01 EDT 2005


Ken D'Ambrosio writes:
 > Okay, this is pissing me off.
 > 
 > I've got a machine, currently "reddwarf", that used to be "nebula".  
 > I've -- obviously -- changed its name.  "nebula" isn't mentioned in 
 > /etc/hosts, and the IP resolves (both reverse and forward) to reddwarf.  
 > /etc/hostname is reddwarf.  The "live" hostname (eg. the output of 
 > "hostname") is reddwarf.  /etc/mailname is reddwarf.  A "strace -f 
 > postfix" doesn't show the word "nebula" anywhere.  "nebula" isn't 
 > mentioned in any of the postfix config files; reddwarf is.  I've made 
 > sure that the postfix processes have restarted.  Hell: I've dpkg 
 > --purge'd postfix (after installing exim), and then installed postfix 
 > again from scratch.
 > 
 > THEN WHY THE FLOCK, WHEN I TELNET TO PORT 25, DOES IT THINK IT'S NEBULA?!
 > 
 > Suggestions as to why this might be would go a long way toward saving 
 > the small amount of sanity I have left.

Ken,

	I guess that if it were me I'd be trying to run postfix under
gdb by now.  You might or might not have to build it from source to
get good symbols, and/or to reduce the optimization level to the point
where the code advances through the source lines in a comprehensible
manner.  It should be easy to grep the sources for where the helo
messages is comming from, breakpoint there, so a stack trace, check
the variables that the code shows in use for generating the "nebula",
grep the sources for references, and if it isn't clear by then,
breakpoint all of the referencers to see who's setting it that way,
rinse and repeat.

	That's if you don't get a good answer from someone else.

	Chances are that the above will only point you to the library
or system call that's still returning the bad stuff.

	Or maybe first try (as root):

   # find /etc -type f -print0 | xargs -0 grep -i nebula | less

							Bill



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