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The company for whom I work have switched broadband provider to B.T. (British Telecomm) using a BT 2700HGV router, I have configured the port forwarding on the router to allow port 1723 and 47 through the firewall and to go to the Linux server running pptp. This does work, however when I connect remotely I cannot telnet to the other servers on the network, I do have a correct local I.P. address and I can ping them and ssh to them.

This did work on the router used on the old broadband connexion. Any thoughts as to what is blocking telnet, surely I am part of the local network with the same restrictions and freedoms as if I were on the LAN?

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47 is a protocol number and not port. For example, TCP is protocol 6 and allowing protocol 6 would allow all ports from 1 to 65535. So you need to find out if you can setup rule for protocol 47 which is GRE. That's why you can authenticate via port 1723 but you cannot pass data over GRE. You might need to pass ALL traffic to your server, and firewall it.

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thank you for the clarification but would that solve, do you think, the problem with being able to telnet to the other servers? – Tim the Enchanter Jun 26 '12 at 6:45

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