daytime service

[Mike Boswell_1]

I would like 'telnet myhost 13' to return the current time on the server. I applied DST patches to all the servers and wanted to test the time change via a script on another machine. When I did this I discovered that the daytime services was not yet using the new DST rules. I had only restarted crond and I did not reboot. What do I need to do the include the correct DST rules into the daytime service? If you suggest restarting inetd, what problems may this cause to other apps or users using this servers resources?

Thanks,
Mike

[Jeff_Traigle · Accepted solution]

You pegged it with restarting inetd. Impact is any services provided by inetd are temporarily unavailable while you bounce the daemon. (A few seconds.) This could range from no impact at all to a major outage. Depends entirely on what's enabled and how your applications use the services.

[A. Clay Stephenson]

Note that daytime is one of the services that is normally disabled because it could lead to a potential denial of service attack. You should really ask yourself if you need this service. Because daytime is an internal (to inetd) service, you will need to bounce inetd for the tztab change to take effect so that the cached tztab entry will be discarded. In this case, sending a SIGHUP to inetd (which is what inetd -c actually does) will not suffice. If you must do this then go to the console and
cd /sbin/init.d
inetd stop
inetd start

It should not cause any current sessions to fail but using the console is the safer method because should anything happen while inetd is down, your console connection can always be re-established.

[Mike Boswell_1]

I dont think I HAVE to do correct the TZTAB data in the daytime service. Unless you guys can think of something dependent on it ??????

[A. Clay Stephenson]

It simply means that any clients which connect to the daytime service will get a wrong timestamp (at least until the time changes according to the old rules). I very much doubt that any clients depend upon the daytime service because there are much more appropriate ways to get the time. Your case is a good example of why it is a good idea to reboot a box after applying the tztab chanes so that you are certain that any long-running processes are restarted. I stronly urge you to disable this service and forget about it.

[Mike Boswell_1]

OK Thanks, Mike