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I want to restrict the sendmail and mysql daemons to listen only on localhost. How would I do this? When I look at netstat, I see that they are listening on all devices (so I guess this means that sendmail would accept emails from the www and I would eventually be responsible for mass spam atrocities).
Once I restrict listening ports for the www to those that I want, is there any further benefit to making rules in iptables that block packets on all other ports? E.g. if nothing is listening on port x for the www, is it still worth blocking packets to port x or is this implicit?
And just quickly, from all the reading I've done over the past couple of days I could not find this out; is sendmail a type of smtp server? If not, what relation does it have to smtp?
Re mysql: Sorry, this is going to sound really dumb, but are you refering to the compile-time configuration file or run-time configuration file? If the second, where can I find it? (I installed from rpm).
Re sendmail: I would like to use php running under apache to send emails and this did not work until I started the daemon. Is there a way to do what you described on this set-up? (php.ini asks for the sendmail path, I put this in with the options -t -i)
Fantastic! Mysql is solved. (They have three example files that's why my.cnf wasn't being found)
In the meantime I was working on iptables (reading the guide at iptablesrocks.org) and I managed to set it up HOWEVER I think I made bo bo. So PLEASE HELP.
I followed the instructions setting up the "saftey net" using a cron to reset iptables every 15min. This seemed to work perfectly since I made a mistake in the set-up file which caused me to loose ssh access, but sure enough when the hour hit I was able to access the server again.
HOWEVER - and this is where my curiosity my have punished me - when I entered "crontab -l" no jobs came up (nothing came up at all, just next command prompt)!!!??!?! So how did the reset happen???
Anyway, I tried to add the job again - this time using emacs instead of vi - and "crontab -l" listed the job. So I thought OK - to hell with it - I don't know what happened but luckily it happened and I was saved. So I typed "crontab -r".
BUT now "crontab -l" prints "no crontab for root"!!!
Have I deleted some "hidden" jobs by accident!!!???