Dear, for some reason we need to change the servers name, of few slave server on a ISPConfig master panel. I know that the servername is set on System -> Server Services and in System -> Server Config. Is it safe to change the server name on these two places? Or we may aspect some side effects? (for example on the remote db access for the customer). Thank you.
That should be ok, it is used in ispconfig interface only. If you change the real hostname of the slave servers then you would have to adjust the ispcsrv* users in the master database as well and all /etc/hosts files.