RROR
The requested URL could not be retrieved While trying to retrieve the URL: http://webmail.xxxxx.nl/imp/redirect.php
The following error was encountered:
    * Zero Sized Reply
Squid did not receive any data for this request.
Your cache administrator is root.
***********

I have checked the httpd error log and could see the below mentioned error:
***********
[root@xxxxxx ~]# less /var/log/httpd/error_log | grep Segmentation
[Mon Feb 06 19:35:33 2012] [notice] child pid 5414 exit signal Segmentation fault (11)
[Mon Feb 06 19:53:57 2012] [notice] child pid 6684 exit signal Segmentation fault (11)
[Mon Feb 06 19:54:21 2012] [notice] child pid 7027 exit signal Segmentation fault (11)
[Mon Feb 06 19:54:57 2012] [notice] child pid 6701 exit signal Segmentation fault (11)
***********

Segmentation fault is due to exceeded file descriptors, i have more than 1024 used:
*************
[root@xxxxxx ~]# ps ax | grep httpd
 1005 ?        Ss     0:02 /usr/sbin/httpd
 1007 ?        S      0:00 /usr/sbin/httpd
 5416 ?        S      1:43 /usr/sbin/httpd
 6333 ?        S      0:40 /usr/sbin/httpd
 6705 ?        S      0:38 /usr/sbin/httpd
 6709 ?        S      0:39 /usr/sbin/httpd
 6718 ?        S      0:39 /usr/sbin/httpd
 7029 ?        S      0:36 /usr/sbin/httpd
 7062 ?        S      0:33 /usr/sbin/httpd
 9156 ?        S      0:18 /usr/sbin/httpd
 9173 ?        S      0:25 /usr/sbin/httpd
11925 ?        S      0:11 /usr/sbin/httpd
11929 ?        S      0:11 /usr/sbin/httpd
11935 ?        S      0:10 /usr/sbin/httpd
12377 ?        S      0:07 /usr/sbin/httpd
12503 ?        S      0:02 /usr/sbin/httpd
12520 ?        S      0:05 /usr/sbin/httpd
12525 ?        S      0:04 /usr/sbin/httpd
12526 ?        S      0:02 /usr/sbin/httpd
12915 ?        S      0:00 /usr/sbin/httpd
12918 ?        S      0:00 /usr/sbin/httpd
12919 ?        S      0:01 /usr/sbin/httpd
13017 pts/1    S+     0:00 grep httpd
[root@xxxxxx ~]# ls -la /proc/1005/fd |wc -l
1154
[root@xxxxxx ~]# find /usr/include/ -name typesizes.h |xargs grep FD_SETSIZE
#define   __FD_SETSIZE      1024
[root@xxxxxx ~]#
*************