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Wynand_van_Nisp's avatar
Wynand_van_Nisp
Icon for Nimbostratus rankNimbostratus
Aug 29, 2006

Websphere and LTM

Hi,

 

 

I am prety new to Irules. I have a client with 3 Websphere servers which each has 4 instances per server running on port 9081...9084. The servers was configured to only accept request on a specic FQDN. eg http://jdedwards.abc.com:9081. When I pass it through LTM the server does not recognise the ip of the VS. Is it possible to write an irule to change the VS ip to the "accepted" FQDN and back when a client connects to LTM.

 

 

Any help would be appreciated.

 

 

Thanks in advance.

 

 

Wynand van Nispen

3 Replies

  • Hi Wynand,

    BIG-IP shouldn't modify the HTTP host header when it sends a request to the node--it should send exactly what it gets from the client.

    If you do want to change the host header with a rule, you can use something like this:

    From the iRule wiki: Click here

    
    when HTTP_REQUEST {
       HTTP::header replace "Host" "my_new_host_string"
    }

    You shouldn't need to rewrite anything on the response back to the client.

    Aaron
  • Deb_Allen_18's avatar
    Deb_Allen_18
    Historic F5 Account
    There was another post last week indicating that WebSphere was squawking about the virtualization.

     

     

    Apparently the WebSphere server is expecting it's own FQDN in the host header.

     

     

    You could create a rule to replace the Host: header for each server with the expected value, using [LB::server addr] to cross reference the IP with the expected hostname using a class.

     

     

    I did some poking around, and found 2 recommended non-iRule approaches to work around this problem.

     

     

    The least invasive way of working around this limitation without an iRule is in DNS: Simply set the forward (A record) resolution of the virtual server name to the virtual server IP, and the reverse (PTR) resolution for each of the pool member IPs to the virtual server name:

     

    virtual server (in websphere.com zone file):

     

    virtualserver IN A 192.168.1.1

     

     

    backend subnet (in .. reverse zone file )

     

    1 IN PTR virtualserver.webshpere.com

     

    2 IN PTR virtualserver.webshpere.com

     

    3 IN PTR virtualserver.webshpere.com

     

     

    The other approach is to actually build ALL the WebSphere servers with the virtual hostname, rather than unique hostnames. The A record for that name would point to the virtual IP, and you can retain the "real" server name as an alias for administration etc.

     

     

    HTH

     

    /deb

     

     

  • Hi

     

    i want use ibm webshpere and ltm,

     

    could you send me your email

     

    i have a few questions

     

     

    regards