My web server is a CentOS box thus:
[root ~]# uname -a Linux mbrc21 2.6.18-92.1.22.el5 #1 SMP Tue Dec 16 12:03:43 EST 2008 i686 athlon i386 GNU/Linux root ~]# rpm -q httpd httpd-2.2.3-22.el5.centos.2
My development and standby is on a Fedora box thus:
[root ~]# uname -a Linux mbrc32 2.6.23.17-88.fc7 #1 SMP Thu May 15 00:35:10 EDT 2008 i686 athlon i386 GNU/Linux [root@ ~]# rpm -q httpd httpd-2.2.8-1.fc7
They are close neighbors on my LAN.
Now I recently revised my httpd.conf making it somewhat more complex and adding ssl for part of it. Running the same configuration on both boxes, I find that the Fedora box runs rapidly, while the CentOS box is very slow.
Examining the situation with WireShark on both boxes I find that in responding to a simple GET, the CentOS box does a sequence of DNS queries to resolve the details of the location of the client IP address, whereas the Fedora box does no such thing. It ts these DNS queries that are causing the slow response.
Now if I revert to the old configuration, there is no such problem and WireShark shows that there are no DNS queries.
Advice on how to proceed would be much appreciated.
Thanks, Mike.