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rwagner1's avatar
rwagner1
Icon for Nimbostratus rankNimbostratus
Aug 09, 2017

iRule Host Header Pool

I'm new to F5 iRule scripting and I'm looking to simplify the following so we don't have to edit the iRule every time we add a new site and pool.

 

Current

 

when HTTP_REQUEST { if { [HTTP::host] eq "abc.123.com" } { pool abc.123.com } elseif { [HTTP::host] eq "def.123.com" } { pool def.123.com } elseif { [HTTP::host] eq "abc.456.com" } { pool abc.456.com } }

 

I would like to simplify this script so that what ever comes in is sent to the pool with out defining each one.

 

The pool name will always match the site. Example site: abc.123.com = pool: abc.123.com

 

Not sure how to write the script

 

when HTTP_REQUEST { if { [HTTP::host] eq "*.123.com" } { pool .123.com } elseif { [HTTP::host] eq ".456.com" } { pool *.456.com } }

 

application delivery
iRules
LTM

1 Reply

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  • CharlesCS's avatar
    CharlesCS
    Icon for Cirrus rankCirrus
    Aug 09, 2017

    This is quick-and-dirty, and doesn't allow for the virtual server receiving a request with an invalid host header:

    when HTTP_REQUEST {
  pool [HTTP::host]
}

    If you want to get fancier, create a data group ("known_hosts", for example) whose entries are valid host names (and for which you've already created the corresponding pool). 

    when HTTP_REQUEST {
  if { [class match [HTTP::host] equals known_hosts] } {
    pool [HTTP::host]
  } else {
     take appropriate action
  }
}