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Forum Discussion

Thomas_Klausen_'s avatar
Thomas_Klausen_
Icon for Nimbostratus rankNimbostratus
May 03, 2017

Using an HTTP monitor without DNS lookup

Greetings.   I have run into an interesting problem... I have an internal F5 LTM configured with a VIP that serves internal clients only. To check on the pool members' health, I use the following ...
application delivery
BIG-IP
LTM
Stanislas_Piro2's avatar
Stanislas_Piro2
Icon for Cumulonimbus rankCumulonimbus
May 03, 2017

Hi,

I think you misunderstood monitor configuration

the 

Send string
is never interpreted by LTM to resolve hostname.

The monitor open a TCP connection to pool member address and pool member port (or alias address / port is configured)

after TCP handshake, the BigIP send the send string as is.

when server respond, it parse the whole response including HTTP headers, if receive string matches, it mark the pool member up and close TCP connection.

if you want to monitor server with URL 

http://appname.companyname.com/authentication.GetServerstatus/appname
, the monitor send string must be :

GET /authentication.GetServerstatus/appname HTTP/1.1\r\nHost: appname.companyname.com\r\nConnection: Close\r\n\r\n