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After following several tutorials on setting up postfix at basic level on CentOs for my VPS, continue to get the following:

-bash-4.1# postfix start
/usr/libexec/postfix/postfix-script: line 317: cmp: command not found
postfix/postfix-script: warning: /usr/lib/sendmail and /usr/sbin/sendmail differ
postfix/postfix-script: warning: Replace one by a symbolic link to the other
postfix/postfix-script: starting the Postfix mail system

In the main.cf below are my edits:

myhostname = myservername.sub.mysite.net
mydomain = sub.mysite.net
myorigin = $myhostname
myorigin = $mydomain 
inet_interfaces = all
inet_interfaces = $myhostname
inet_interfaces = localhost
mydestination = $myhostname, localhost.$mydomain, localhost
mynetworks =,

Also removed sendmail but haven't yet set up db, just trying to get postfix to start without errors.

Is this the problem? why are two files in red? usr/sbin

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What's the output of which cmp? The first line suggests to me that postfix is running sanity checks which rely on it. (Strange, I've never seen an install without it.) –  Ulrich Schwarz Dec 12 '12 at 7:01
the output of the command. For me, it's ~ % which cmp giving /usr/bin/cmp –  Ulrich Schwarz Dec 12 '12 at 9:43
I can't find what you are talking about sorry? –  freja Dec 12 '12 at 10:08
/usr/bin/which: no cmp in (/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin) –  freja Dec 12 '12 at 10:09
Installed: diffutils.i686 0:2.8.1-28.el6 Complete! -bash-4.1# postfix stop postfix/postfix-script: stopping the Postfix mail system -bash-4.1# postfix start postfix/postfix-script: starting the Postfix mail system -bash-4.1# –  freja Dec 12 '12 at 10:21
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1 Answer

up vote 1 down vote accepted

You're probably lacking the diffutils package, which will provide the cmp binary that postfix needs for its sanity checks.

sudo yum install diffutils

should help you on.

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thanks - see above already worked that out –  freja Dec 12 '12 at 10:31
you were a few minutes too late with your answer :P –  freja Dec 12 '12 at 10:31
can u tell me mistake here pls? -bash-4.1# postconf -e postfix_mydestination = localhost burra.yabbit.net postconf: fatal: missing '=' after attribute name: "postfix_mydestination" –  freja Dec 12 '12 at 10:32
@freja: Sorry, I'm not a mail person at all really. –  Ulrich Schwarz Dec 12 '12 at 11:23
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