2) When I am working in a website I get a lot of 500 Internal Errors... But if I wait 2 or 3 seconds and then refresh my browser, everything is back to normal again. How can I avoid this kind of situation? Is there anything that I could set to solve this issue once for all ?
I don’t know–I’ve never seen this particular issue. It could be a broken mod_fcgid. Ubuntu has a history of shipping broken mod_fcgid packages…so it could be that. What appears in the error_log when one of these errors occurs? (Make sure you’re getting the entry that is triggered when the 500 occurs…not just random stuff from the log…the best way to do that is probably to “tail -f” the log, hit enter a few times so you can see where the break is…and then reload your page until the 500 error occurs…if something shows up in the log at that moment, that’s what we want to see).
“3) Some weird thing is happening with my customers email accounts… If I try to send an email via thunderbird/outlook (my email account is in another server running cpanel), it isn’t delivery to the email account in my webmin/virtualmin server, and the funniest thing is: a) there is no record in my log files about this email and b) If I send an email via my yahoo account or via this specific customer website (using a php form), it works!!! On the other hand, if that specific account send me an email via webmail or an email client (ie: thunderbird, outlook) it works perfectly.”
You you don’t see an entry in the maillog when this happens, then you’re not actually sending mail through your server. I can’t really tell you why that’s so, there are several possibilities.
If your ISP is evil, they might be hijacking SMTP connections (seems unlikely) and then doing something dumb with the resulting messages.
More likely is that the domain name your mail client is connecting to is resolving to the wrong place. You might try changing it to the IP address of the server, so you can be absolutely certain it’s going to the right system.
As I said, if it’s not in the log, then the server isn’t in the path of the email, and there’s nothing to be done at the mail server level. You’ve got to find out why mail is never coming to your server, not why the server isn’t delivering it.
4) Very soon I will need to recompile my php to allow MSSQL database connection (via freetds) to an external server, is there any tip/trick to do that via webmin/virtualmin?
I’ve got no clue. Can’t that connector build as a module, perhaps? That way you’d just install the -dev or -devel package, and build the module without having to replace the whole thing. If you do have to replace it, install the php source package via apt or from SRPM and see about rebuilding it with the bits you need (or at the very least make note of the configure options from the default package).
5) And finally, whenever I create a new virtualhost I have to manually fix the new *.host file in /etc/apache2/sites-available (changing the <virtualhost *:80> to <VirtualHost MyServerIP:80>). Is there something that I can set to make it automaticaly?
Yes, kill the NameVirtualHost *:80 bit in the Apache configuration, first off. You don’t want it in a virtual hosting environment (it’s setup by default in the Ubuntu configuration, unfortunately). You can find the offending line with a grep /etc/apache2 (I don’t remember which of the half-dozen configuration files on Ubuntu contains it):
grep -r NameVirtualHost *
And, for Virtualmin the configuration is documented here:
http://www.virtualmin.com/documentation/id,troubleshooting_common_problems/#the_wrong_site_shows_up