Do you have php-mysql installed?  Did you restart httpd after you 
installed it?

Matt Graham wrote:
> After a long battle with technology, Steven A. DuChene wrote:
>   
>> But if that was the problem then the command line invocation on the Apache
>> server should not work. I.E. if it was a port or firewall issue.
>>     
>
> apache:~$ mysql -u user --password=BLAH --host Mysql
> apache:~$ php -r '$c=mysql_connect("Mysql","user","BLAH"); if(!$c){ 
> die("barf:".mysql_error()); }'
>
> ...both should work.
>
>   
>>>> Can't connect to MySQL server on 'Mysql' (13)
>>>> in /home/minime/public_html/testmysqlconnect_script.php on line 6
>>>>         
>>> Are you running in safe mode?  Is Mysql's mysqld listening on port 3306? 
>>> Is there any firewall in the way on that port?
>>>       
>
> No firewall.  Are you running php-web in safe mode?  Take a really good look 
> at the settings for mysql in your php.ini, and make sure they're all right.
>
>   
>> Apache system is running Fedora9 while the Mysql system is a OpenSuSE-10.1
>>     
>
> SuSE is buggy, but the problem as you've described it is not a SuSE bug.  The 
> shotgun debugging approach would be to start up "tcpdump -s0 -w dump.pcap 
> port 3306" on apache, then run both the mysql command-line client connect 
> attempt and the bad PHP script on apache.  Then stop the tcpdump, then look 
> at dump.pcap with wireshark, then play "one of these things is not like the 
> other".
>
>