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iNTERCELL_GROUP's avatar
iNTERCELL_GROUP
Icon for Nimbostratus rankNimbostratus
Mar 23, 2011

2 Diff VIPS with different Pools, but Pool Members with the same IP and Port

Hi Guys!

 

 

I am new to these forums and very excited to join and hope to contribute if I can. I only have been working with F5 LTMs and GTM's for the past 5 yrs but on and off. I am pretty familiar with the platform and quite comfortable.

 

 

My question is I am working on a big migration and I am coming across many issues where the applications don't work completely due to some 3rd party handler on the application. I recently came across some VIP on port 80 with completely different websites that have different pools, but the pool members have the same IP address and Port 80 on running on their server node's IIS Binding.

 

 

When we first added the members,the server nodes were running the different sites on different ports such as: 81, 82 with the VIP still running on port 80. However, as I stated above, the 3rd party handler's on the server's default port is 80. So the developers asked me to use port 80 on the pool members instead of port 81, and 82 for testing, and it worked. But the 2 different sites are on the same server and all configured in IIS. So here is the summary:

 

 

VIP: x.x.101.101 = http://something.domain.com

 

Port: 80

 

 

Pool Members:

 

x.x.34.10 Port 80 (IIS Binding)

 

x.x.34.11 Port 80 (IIS Binding)

 

 

External DNS Binding in IIS = http://something.domain.com

 

 

VIP: x.x.101.102 = http://something1.domain.com

 

Port: 80

 

 

Pool Members:

 

x.x.34.10 Port 80 (IIS Binding)

 

x.x.34.11 Port 80 (IIS Binding)

 

 

External DNS Binding in IIS = http://something1.domain.com

 

 

The application team has 2 other sites set up the same way. I am confused on to how this will work, how does the F5 no where to send the request to and actually pull up the correct website since they are both running on the same server with the same IP Address and Port. They said that the site is working fine now since the Pool Member change to Port 80 from ports 81 and 82 as well as their IIS binding.

 

 

Thanks Guys I really appreciate the help! Any explanation will be greatly honored!

 

 

 

ICG

 

 

config
design
  • Nathan_Houck_65's avatar
    Nathan_Houck_65
    Icon for Nimbostratus rankNimbostratus
    Mar 23, 2011
    I believe this is handled by IIS, not the bigip. I assume that the IIS server is using Virtual Hosting and the hostname specified in the http header is how the correct content is being served up.
  • Chris_Miller's avatar
    Chris_Miller
    Icon for Altostratus rankAltostratus
    Mar 23, 2011
    Welcome! It's great to hear you're looking forward to contributing.

     

     

    IIS is actually doing the hard work here. LTM will send the requests to the same pool members which will then return the necessary content. This is typically done by reading the "host header."

     

     

    When a user hits http://something1.domain.com, their host header would be "something1.domain.com." IIS reads this and sends it to the correct "site."

     

     

    Here's a decent Microsoft overview on how this works - it's for IIS 6.0 but the same logic applies in 7.

     

     

    http://www.microsoft.com/technet/prodtechnol/WindowsServer2003/Library/IIS/e7a21b1f-ab13-47f2-8c61-b09cf14a7cb3.mspx?mfr=true