ACE configuration to 11.4.1

I'm new to BigIP, but I'll be in your boat very soon.

First, you need to know what your current Probe is doing.

Official Cisco-ese can be a bit dry. So, in short you have.

 probe http test   - command type name
 description test 
 port 80           - static port [real-server / member port is ignored]
 interval 30       - seconds between tests
 passdetect interval 60  - seconds between tests for a failed server
 receive 15        - seconds to wait for data/reply
 request method get url /validation/default.aspx  - retrieve file
 expect status 200 403  - pass if reply status is between 200 and 403, inclusive
 hash B8477B9B88E90F12E3200660A70EB765  - verifies the page content hash hasn't changed
 header Host header-value "idk.howtoconfigurethis.net"  - HTTP header sent to server
 open 15  - seconds to wait for initial SYN-ACK  [must be smaller than interval]

I believe the following TMSH should get you close; only missing the hash check.

 monitor test '{ 
   defaults from http 
   description test 
   destination *:80 
   up-interval 30 
   interval 60 
   timeout 91 
   recv "HTTP/1\.(0|1) (2..|403)"
   send GET "/validation/default.aspx HTTP/1.1\r\nHost: idk.howtoconfigurethis.net\r\nConnection: Close\r\n\r\n"}'

Should just need to remove the returns and enter it as one line in TMSH