Problem with web based apps

["B. J. Zolp" <bjz@dewittross.net>]

   Hello, my firm has several ldap servers for managing contact and 
employee info.  These ldap databases are accessed via two php based web 
front ends written by a former employee.  Recently I have had to replace 
the two servers that these web based front ends run on.  Although I am 
fairly familiar with ldap, I have similar issues with both replacements...

1.     In replacing the first server I decided to do a fresh install of 
the latest Redhat to bring it up to date from the old Redhat 6.x that 
was on the old box.  With this machine the front end and the ldap server 
are actually on the same box so after successfully importing the ldif 
from the old server I moved the php code to the appropriate directory 
and gave it a try.  The php executes fine, but when accessing anything 
from the ldap database it will fail saying it is unable to access the 
ldap database  (checked logs for both apache and ldap server and found 
no errors).  However, when I simply execute this code while the old 
server is up and on the network it will access the ldap DB from it just 
fine, but when I take the old one down and switch hostname and IP to 
make the new machine similar to the old, it gives me the access problem.

   I also tried simply copying the old DB over without doing an import 
of an ldif with similar results.  Additionally, I did a fresh install of 
the same redhat version that is on the old server with similar version 
of ldap, php, and apache.  This also had similar unwanted results.  Only 
when I did a direct dd copy of the old machine to the new one did I get 
a new working system.  So  I managed to get this working  well enough, 
but these issues lead me to my second current problem, which is more 
important. I thought I would include this first account of my 
experiences in order to perhaps help other readers gain any insight as 
to what I am doing wrong or perhaps overlooking.


2.   This current server replacement is different from the first in that 
the ldap DB is not local and is left untouched in the upgrade of this 
server.  The server I am replacing is basically a straight up web server 
that accesses the external ldap server with one php web application for 
employee data.  I started with a fresh current distro install and moved 
the www documents and php over to the new box.  After configuring the 
machine with the same ip/hostname as the box it is replacing I hooked it 
to the network and tested it out.  All webpages and php code is served 
up fine, but I get a similar problem where it cannot access the ldap 
server whenever I attempt to lookup data.  I know that the machine can 
access the ldap server via hostname/IP over ping and other network 
apps.  So I am at a loss as to what is causing this problem. 

Long story short: what do I have to do to be able to drag a php web app 
over to a new box and get it to run on there?


Any help or questions for clarification would be great.

thanks,

B. J. Zolp