How to log hostname on LTM if its not http request

If I may add, almost anything is possible, but you have to think about each situation in terms of the protocol you're dealing with. HTTP is a plain text protocol and a request generally includes a "Host" header that is easily available for logging. Telnet and FTP, however, do not pass host name information in the protocol. They simply connect to an IP address (that may have been resolved from a host name on the client side). You could certainly log the layer 4 data though (source and destination addresses). That would be universally available to all protocols. Telnet and FTP are also, for the most part, clear text, so it wouldn't be too difficult to log activity within the respective sessions.