iRule Redirect and mask destination URL

Hmmm. Maybe I'm missing something. I was able to create the external file based datagroup without a problem. But I'm not clear on how to configure a server off of my network as a node in one of my pools. I am looking to do a pass-thru reverse proxy, none of the assets or content is hosted in my network.

 

 

BTW, THANK YOU SO MUCH FOR ALL THE HELP!!!

Can you hardcode the IP address(es) that the external domain resolves to? Or do you need to do a DNS lookup of the hostname? If the former, you can configure the IP address:port combinations in the pool. If the latter, you can use NAME::lookup in pre-10.1 or RESOLV::loookup in 10.1+ to resolve the hostname. For NAME::lookup, I can post an anonymized iRule example to do a look up every X seconds in the next couple of days.

 

 

Aaron

Thank you so much for your help! Finally got this working through HTTP now to get the SSL side done. Again, thanks for all your help.

 

 

--Shawn

Hi,

 

 

I have the same issue. I want to proxy to urls that are not in our network. And I can't make a pool, because we have to resolve the name on the fly.

 

To give you an example so you can understand what we are trying to accomplish.

 

We have made some google app, but want the apps to have a mycompany.com url:

 

http://appname.mycompany.com/ -> http://appname.appspot.com/

 

We don't want a redirect, and we should rewrite the response as well. I thought ProxyPass would work, but the trouble is that I can't make a pool of a domain name.

 

 

- Jojo

Hi Jojo,

Which LTM version are you running? For 9.x - 10.0.x you can use NAME::lookup to resolve a hostname to an IP address. For 10.1.x and higher, you can use RESOLV::lookup

http://devcentral.f5.com/wiki/default.aspx/iRules/NAME__lookup

http://devcentral.f5.com/wiki/default.aspx/iRules/RESOLV__lookup

You might want to implement logic to cache the IP address for x seconds. Here is a rough web proxy example which does this. Note, I wouldn't suggest using the proxy functionality, but hopefully it gives you an idea of how to use NAME::lookup.

Aaron

 web proxy example

 This is a simple, incomplete example web proxy iRule.
 It only supports limited proxy functionality of converting the requested host 
    (from an absolute URI or the Host header) to an IP address and sending the request on.  
 It doesn't support CONNECT/HTTPS or most other RFC2616 requirements for a web proxy.

when HTTP_REQUEST {

   log local0. "[IP::client_addr]:[TCP::client_port]: New HTTP [HTTP::method] request to [HTTP::host], [HTTP::uri]"

    Check if the URI is absolute and http://
   if {[string tolower [HTTP::uri]] starts_with "http://"}{

       Parse the host value from the URI
      set host [URI::host [HTTP::uri]]
      log local0. "[IP::client_addr]:[TCP::client_port]: Parsed $host from URI [HTTP::uri]"

   } else {
      set host [HTTP::host]
   }

    Check if host header has a port
   if {$host contains ":"}{

       Scan the host header to parse the host and port
      if {[scan $host {%[^:]:%s} host port] == 2}{

         log local0. "[IP::client_addr]:[TCP::client_port]: Parsed \$host:\$port: $host:$port"

      } else {
          Host value was host: without a port. Use the requested port.
         set port [TCP::local_port]
      }
   } else {

       Host header didn't have a port. Use the requested port.
      set port [TCP::local_port]
   }
    Check if the host header isn't an IP address (ie, it contains an alpha character)
   if {[string match {*[a-zA-Z]*} $host]}{

      log local0. "[IP::client_addr]:[TCP::client_port]: Host value not an IP: $host"

       Perform a DNS lookup of the hostname
      NAME::lookup $host

       Hold the request until name resolution completes
      HTTP::collect

   } elseif {[catch {IP::addr $host mask 255.255.255.255}]==0}{

      log local0. "[IP::client_addr]:[TCP::client_port]: Host is an IP: [HTTP::host]"

       Request was to a valid IP address, so use that as the destination
      node $host $port

   } else {

       Couldn't parse host header.  Could use the destination IP address as the destination?
      HTTP::respond 400 content "Invalid Host header"
      log local0. "[IP::client_addr]:[TCP::client_port]: Invalid host header: [HTTP::host]"
   }
}
when NAME_RESOLVED {

   set response [NAME::response]

   log local0. "[IP::client_addr]:[TCP::client_port]: Resolution response: $response (elements: [llength $response])"

    Check if there is a resolution answer and it's an IP address
   switch [llength $response] {

      0 {
          No response, or response wasn't an IP address
         log local0. "[IP::client_addr]:[TCP::client_port]: Non-existent/invalid response: $response"
 HTTP::respond 500 content "Couldn't process request"
      }
      default {

          Response was one or more list entries.  Use the first list element.  Check if it's an IP address.
         if {[catch "IP::addr [lindex $response 0] mask 255.255.255.255"]==0}{

             Request was to a valid IP address, so use that as the destination
            if {$port != "" and [string is integer $port]}{
               log local0. "[IP::client_addr]:[TCP::client_port]: Using destination with parsed port [lindex $response 0]:$port"
               node [lindex $response 0] $port
            } else {
               log local0. "[IP::client_addr]:[TCP::client_port]: Using destination with default port $response:[TCP::local_port]"
               node [lindex $response 0] $::default_port
            }
         } else {
             No response, or response wasn't an IP address
            log local0. "[IP::client_addr]:[TCP::client_port]: Non-existent/invalid response: $response"
    HTTP::respond 500 content "Couldn't process request"
         }
      }
   }
    Release the request
   HTTP::release
}