iRule for Server Testing

Hi Guys,

Thanks for replying - this is truly a big help. I now have a better understanding of how this all works and have been analyzing the results captured with tcpdump. Here is what I am seeing:

If I issue the following (via telnet):

telnet blacks.test.pnimedia.com
GET / HTTP/1.1
HOST: blacks.pnimedia.com

Everything works fine and I get the expected content.

*However*, via the rule I have created according to your posts everything seems to be correct. Is it possible that the HTTP/1.1 header is not being included in the request down to the node? I am seeing this (as expected) in the 'ltm' logs:

Rule PNI_TestProcessor : Replacing host from blacks.test.pnimedia.com to blacks.pnimedia.com
Rule PNI_TestProcessor : Searching for node: web002
Rule PNI_TestProcessor : Routing to node: 10.10.20.51 

Which is correct!

Tcpdumps, however, reveal a different story. The external dump captured was as follows:

tcpdump -w /var/tmp/external.dump -ni external port 80 and host 64.85.47.204

The internal dump captured was as follows:

tcpdump -w /var/tmp/internal.dump -ni internal port 80 and host 64.85.47.204

Both of these are attached, but as a summary it looks like request is malformed.

For reference, here is what is in the rule "PNI_TestProcessor" which I have attached to the VS in question:

when HTTP_REQUEST {
 Search for host mapping in the lookup list
set new_host [findclass [HTTP::host] $::host_mapping " "]
if { "" ne $new_host } {
 if mapping is found, replace the Host header
log local0. "Replacing host from [HTTP::host] to $new_host"
HTTP::header replace "Host" $new_host"
 Pull out the node name as the first element of the uri
 ie. /web001/foo/bar -> web001
set node_name [lindex [split [HTTP::uri] "/"] 1]
if { "" ne $node_name } {
 Now look for the node address in the lookup list
log local0. "Searching for node: $node_name"
set node_addr [findclass $node_name $::node_mapping " "]
if { "" ne $node_addr } {
log local0. "Routing to node: $node_addr " 
node $node_addr
} else {
log local0. "Didn't find node '$node_name' in lookup class"
}
} else {
log local0. "No node name passed in URI"
}
} else {
log local0. "Didn't find [HTTP::host] in lookup class"
}
}

Do you guys have any ideas on this?