[CentOS] postfix install error: fatal file /etc/postfix/main.cf: parameter setgid_group: unknown group name: postdrop

Tue Aug 26 14:17:14 UTC 2008
Rainer Traut <tr.ml at gmx.de>

Hi,

sys: Centos 5.2 x86_64

Trying to switch from sendmail to postfix I did:

# yum remove sendmail

which resulted in erasing of:
mdadm sendmail-doc sendmail sendmail-cf mutt fetchmail redhat-lsb 


I did then:

yum -y install redhat-lsb.x86_64 postfix

and got this error:

   Installing: postfix                      ######################### [1/2]
postfix: fatal: file /etc/postfix/main.cf: parameter setgid_group: 
unknown group name: postdrop
warning: group postdrop does not exist - using root
warning: group postdrop does not exist - using root
warning: group postdrop does not exist - using root
warning: group postdrop does not exist - using root
   Installing: redhat-lsb                   ######################### [2/2]

I checked and indeed there is no group postdrop on the system.
On an El5 system I see the group.

Thx
Rainer