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gossett_151899's avatar
gossett_151899
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Aug 12, 2014

I have a very basic noob question. How do the servers in the load balancing pool know how to use the virtual server IP address?

My question is this: how do the servers in a load balancing pool know to use the virtual server IP address? Example:

 

server 1 server 2

 

virtual server IP x.x.x.x

 

how do server 1 and server 2 know to use the IP of the virtual server as it is set up in the F5 for load balancing. I've never set up this before, just got thrown into it and they want it now.

 

11 Replies

  • Typically end user traffic is directed to the virtual server, which then load balances the connection across the two backend servers. The return traffic from your servers will either route back out through the BIG-IP (specifying it as a default gateway for example) or the BIG-IP will use source NAT (SNAT) to ensure that all return traffic from the servers comes back through the BIG-IP.

     

    Hope this answers your question. If not, keep 'em coming.

     

    • gossett_151899's avatar
      gossett_151899
      Icon for Nimbostratus rankNimbostratus
      Typically end user traffic is directed to the virtual server. This is my man concept I can't get my head around. How does the end user traffic know where to go. For example i'm sitting on a server doing my work. How does it even know to check with the virtual server in the F5 system. Maybe i'm over complicating it I just don't understand. Does anything need to be set up on the servers that are in the load balancing pool?
    • Cory_50405's avatar
      Cory_50405
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      Typically something like this: End user wants to access your application. Types the FQDN corresponding to your application into his browser, http://www.example.com for example, which DNS resolves to the IP address on your virtual server. BIG-IP then proxies the connection through to the backend servers. So DNS configurations would need to be in place as well, unless you are accessing the application directly by IP address. In this case, that IP address would be the virtual server address.
    • gossett_151899's avatar
      gossett_151899
      Icon for Nimbostratus rankNimbostratus
      I think i'm still not explaining it right. What you said make perfect sense but this is what I need. No one will use the browser (that I know of; this may be where i'm confused). Basically I have two servers that do the same thing. Want to set up F5 so if one goes down it switches to the other one. How does the virtual server IP play a part in this kind of setup?