On Mon, 2005-10-24 at 08:40, Kai Schaetzl wrote:
I made a yum update to 4.2 yesterday. The first "major" update I did on CentOS, I'm only using it for a few weeks now, starting with 4.1. Mainly for evaluation for a prospected migration from Suse to CentOS. Basically the update went very well, fast (only 180 MB needed to be installed) and smooth. But there were two small issues where I don't know why they happened:
- sshd seems to start twice or so since that update. No problems with
ssh, though.
from boot.log: Oct 24 14:00:16 nx05 sshd: succeeded
from warn log: Oct 24 14:00:16 nx05 sshd[1737]: error: Bind to port 22 on 0.0.0.0 failed: Address already in use.
Same thing happens when I restart sshd and even when I reload it. There was a new sshd_config installed, I think I read something about removing ssh 1 protocol from it. This can't be the cause. There's only one instance of sshd running apart from the children for actual logins. Why is this happening, how to fix it?
Most of the times I have seen this it is caused due to having IPv6 enabled. ssh binds to the port on IPv4 address or IPv6 then tries to bind a second time to the same port.
Personally I usually disable IPv6 and the zero conf stuff on systems. Have not had a use for either of these on systems and I suspect the zero conf stuff could lead to security issues if/when someone studies it a little more. :)
There is another question that arises in this context: will a yum update always overwrite with new configuration files, if that file got changed from the originally installed one? I'm used from Suse that new configuration files get saved with another extension if the original file got changed or in some cases it overwrites the file but copies the old file to a backup. I can also expressly exclude some config files from overwriting via sysconfig (if I remember correctly), can I do similar with CentOS?
Many rpm packages will typically not over write configuration files that have been modified. They will create a .rpmnew file for the config file. But don't count on that action. Backups are good to have of any configuration files you have changed.