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Forum Discussion

puluck's avatar
puluck
Icon for Cirrus rankCirrus
Sep 04, 2014

Http header

Hi All,

 

I wanted to insert http header on URL for backend server selection .So if XYZ.abc.com is URL and if the traffic hits the F5,it should insert header of backend server ,say server 1 ,so request should go to server 1 .I have multiple server in backend so not sure how i can achieve this .What are the best option to do that .

 

Is their any impact on F5?

 

2 Replies

  • nitass's avatar
    nitass
    Icon for Employee rankEmployee
    Sep 04, 2014

    do you mean you want to select server and insert http header based on hostname in url (host header)?

     

    if yes, you can check host header using HTTP::host and insert header using HTTP::header command.

     

    HTTP::host

     

    https://devcentral.f5.com/wiki/iRules.http__host.ashx

     

    HTTP::header

     

    https://devcentral.f5.com/wiki/irules.http__header.ashx

     

    if there are multiple hostnames, you may store them in data group and search it using class command.

     

    class

     

    https://devcentral.f5.com/wiki/irules.class.ashx

     

  • nitass's avatar
    nitass
    Icon for Employee rankEmployee
    Sep 05, 2014

    I have URL xyz.abc.com now when client hits this URL ..F5 should insert http header with server name ,which server request should be forwarded .

    do you want to manually select server and insert custom http header based on hostname in url (host header)?

    or

    do you want to rewrite http host header based on load balanced server?

    this is an example of the latter one.

     config

root@(ve11a)(cfg-sync In Sync)(Active)(/Common)(tmos) list ltm virtual bar
ltm virtual bar {
    destination 172.28.24.10:80
    ip-protocol tcp
    mask 255.255.255.255
    pool foo
    profiles {
        http { }
        tcp { }
    }
    rules {
        qux
    }
    source 0.0.0.0/0
    source-address-translation {
        type automap
    }
    vs-index 7
}
root@(ve11a)(cfg-sync In Sync)(Active)(/Common)(tmos) list ltm pool foo
ltm pool foo {
    members {
        200.200.200.101:80 {
            address 200.200.200.101
        }
        200.200.200.111:80 {
            address 200.200.200.111
        }
    }
}
root@(ve11a)(cfg-sync In Sync)(Active)(/Common)(tmos) list ltm data-group internal servername
ltm data-group internal servername {
    records {
        200.200.200.101/32 {
            data server101
        }
        200.200.200.111/32 {
            data server111
        }
    }
    type ip
}
root@(ve11a)(cfg-sync In Sync)(Active)(/Common)(tmos) list ltm rule qux
ltm rule qux {
    when HTTP_REQUEST_SEND {
  clientside {
    HTTP::header replace Host [class lookup [LB::server addr] servername]
  }
}
}

 trace

[root@ve11a:Active:In Sync] config  ssldump -Aed -nni 0.0 port 80
New TCP connection 1: 172.28.24.1(38986) - 172.28.24.10(80)
1409877091.1710 (0.0015)  C>S
---------------------------------------------------------------
GET /attempt1 HTTP/1.1
User-Agent: curl/7.15.5 (i686-redhat-linux-gnu) libcurl/7.15.5 OpenSSL/0.9.8b zlib/1.2.3 libidn/0.6.5
Host: 172.28.24.10
Accept: */*

---------------------------------------------------------------

New TCP connection 2: 200.200.200.14(38986) - 200.200.200.111(80)
1409877091.5871 (0.4142)  C>S
---------------------------------------------------------------
GET /attempt1 HTTP/1.1
User-Agent: curl/7.15.5 (i686-redhat-linux-gnu) libcurl/7.15.5 OpenSSL/0.9.8b zlib/1.2.3 libidn/0.6.5
Host: server111
Accept: */*

---------------------------------------------------------------