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superfxp

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How to get the correct IP address on web sites with load balancing

HI Experts,

My company is using a proxy server that allow access by IP addresses instead of by domain name (not like ISA server).

Every time when users request to add more URL on the allow list, I have to ping the URL and enter the IP address to the list in order to grant access. However, I've been expericencing some domain names replies with different IP addresses every time I ping it. And none of the IP seem real IP because I try to put the IP on the URL and it did not take me to the web site.

My question is, for this situation how can I find the real IP address so that I can enter it to the list and grant access to the users
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ravenpl
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*nix like

host -t A www.thedomain.com

*indows
nslookup
> set type=A
www.thedomain.com

both shall print all currently assigned IPs
I would say that you need to find a way to use URL and not depending on IP.  Websites that are using static IP are in small number in compare to the cases that you are encountering.  Here are some cases:
1.  Web hosting companies assign one IP to make sites and depend on host-headers -  allow this IP mean you are allowing all those sites which use this IP also.
2.  Load balancing, round robin, web acceleration - you are hitting the front-end and not the web server back end - IP may change as it transverse the front end to back end web server
3.  Site redirections - for example, hotmail.com is now live.com
4.  DynDNS ...
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When you are using website name there is no guarantee that the IP address will not change. Also, many web servers sit either behind a firewall or a load balancer that hides the actual IP address of  these servers, which could be a NATed IP. So, to get IP address of a site you use dns that might return one or more IPs if  the website is served by multiple servers.
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superfxp

ASKER

Thank you for the replies.

I understand that when I ping the url it will only hitting the firewall not the actual web server but is there any way I can get the real IP for the URl.

Also, it is a good suggestion to change using domain name instead of IP however, my company will not change to a different Proxy solution.
> I understand that when I ping the url it will only hitting the firewall not the actual web server but is there any way I can get the real IP for the URl.
If it's behind firewall/loadBalancer - no, You can't.
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Carlos Hernandez
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Cloz, so another word. As long as the proxy have the correct IPs of the web site and when users type the web address it hit the proxy and proxy allow to go that range of IP and it will work correct?

I thought You wanted all addresses for given name. Answer for that is in the first post. Have You forgot the original question You have asked?