RFC 3620:The TUNNEL Profile
RFC-Ref

Telnet


Click on the red underlined text to get to the source

... destination is not a BEEP server. (Of course, specifying the telnet service can be expected to lead to this error.) The same would result if the destination ...
... port='604'> <tunnel fqdn='final.example.com' srv='_telnet._tcp'> <tunnel/> ...
... element looks like this: <tunnel fqdn='final.example.com' srv='_telnet._tcp'> <tunnel/> ...
... port='604'> <tunnel fqdn='final.example.com' svc='_telnet._tcp'> </tunnel> ...
... element looks like this: <tunnel fqdn='final.example.com' srv='_telnet._tcp'> </tunnel> ...



Google
Web
RFC-Ref