On CentOS i do not have: /root/ispconfig/httpd/conf/httpd.conf Any ideas? I am running into the same issue when using both NICs, using only one NIC, if i switch the IP to a different address the 400 error instead of showing the host name www.mydomain.com reverts to localhost.localdomain. If i switch back to the IP that i was originally using it goes back to www.mydomain.com. Any idea why this happens? Where does the localhost.localdomain get pulled from? The only place i can find it is in my hosts file. This may help with a solution to my issue, when i ping the host name it, www.mydomain.com, it comes back with; localhost.localdomain 127.0.0.1 and not the hostname itself with the IP, im guessing i did not change it in ISPConfig someplace unless the issue is what is in my hosts file.