The telnet command would be: "telnet google.com port 80" or in your case "telnet gateway1.hosted.carriername.com port 447". Please see below for explanation:
vrf - Open a telnet connection on a specified VRF
WORD - Telnet destination address (A.B.C.D) or hostname
router#telnet google.com ?
port - TCP port
router#telnet google.com port ?
<1-65535> - Configure an alternate port for this telnet session
router#telnet google.com port 80
Trying google.com...Press Ctrl+C to abort
% Connection Established
Be sure you have a DNS entry in your config that is reachable to resolute the name.
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