Problem was/is: After upgrading to CentOS 5.6, the ssh server did not start which can be somewhat "embarassing"...
On the console I get the following:
[root@douala pascal]# /etc/init.d/sshd start
Starting sshd: Auto configuration failed
9009:error:0E065068:configuration file routines:STR_COPY:variable has no value:conf_def.c:629:line 228
[FAILED]
[root@douala pascal]#
Explanation and solution is very simple:
The new openssh-Packages from CentOS/Redhat 5.6 changed the behaviour when it comes to usage of the openssl-libraries.
The updated sshd versions do check
If you made any reference to an environment variable in this config file, openssl will not be able to initialize.
In my case it was a
Because I wanted to set multiple Subject Alternate Names in my certificate requests based on the setting of an environment variable.
If this variable is not set, sshd will not start.
So you have two possibilities:
1. Define the environment variable or
2. Just don't use them and use a different config file for the certificate request creation process.
Result:
The updated sshd versions do check
/etc/pki/tls/openssl.cnfIf you made any reference to an environment variable in this config file, openssl will not be able to initialize.
In my case it was a
subjectAltName=$ENV::SANBecause I wanted to set multiple Subject Alternate Names in my certificate requests based on the setting of an environment variable.
If this variable is not set, sshd will not start.
So you have two possibilities:
1. Define the environment variable or
2. Just don't use them and use a different config file for the certificate request creation process.
Result:
[root@douala pascal]# /etc/init.d/sshd start Starting sshd: [ OK ] [root@douala pascal]#

Thank you!
It is not only that sshd deamon won't start - sshd wouldn't even spawn a new process (for establishing new session).
One more for my 'is it a bug or a feature' list. :P