Unfortunatly I have to change the root password on my red hat server.. If I'll change it, may i have any problem with application (or software) that were working until now?? outlook, mail server, vpn, ecc..
I this case can I re-insert the old password in order to make them to return to work correctly??
Thanks a lot!

Changing the password will not have any effect, besides you having to remember a new password.

1 members found this post helpful.

A normal answer is TobiSGD's reply.

I guess it could be possible that some issue comes up. Normally, linux doesn't rely on the password as a text, it relies on the authentication as a go no-go. It could be possible I guess to do some odd things.

Really could get into some issues depending on how you authenticate the user. Some network or maybe some encryption issues. Some deployment of passwords over the scope of the interconnected computers.

Be sure to have a good backup of the system to be sure.

Some passwords can't be simply returned. They require a few things to develop the password not simply your text. One might be a high precision clock to add in to hash. Almost impossible to duplicate that.

Take a backup of /etc/shadow before you change your password as this file will contain the encrypted password hash for your root user. You could then always restore your backup of this if you did have some kind of unforeseen issue.

As far as I know root passwords on servers needs to be changed frequently and then passwords have to be really tough so that it is harder to crack it. Again I have changed my root password many times but then it is no big deal. I am not sure what is OP is asking and if he is asking something as basic as changing the root password what is he doing on a server?
I am confused now.

I think the OP is just concerned about any possible impact of making this change on his apps/users of this server. Prudent to think things through when you're unsure, but I think we all agree in this case this is a standard administrative task that should not normally be expected to result in any issues (aside from needing to remember the new password as already mentioned!).

In the first place you shouldn't have root-login enabled and also use key-based authentication. Possible attackers can try to crack the password the whole day, they will still not be able to log in.

I change mine every 60 days, the biggest drawback is for a couple days I keep putting in the old password. (system doesn't care that the password is changed it just doesn't let me in if I don't put the correct one).