I have just purchased a Draytek 2710n and I'm trying to get it to work with my Windows 2003 server. I have forwarded port 1723 traffic to my server (NAT > Open Ports > 1723 > 192.168.0.1)

Unfortunatley this doesnt appear to work and looking at the syslog the Draytek itself is trying to authenticate. On older versions of Drayteks I have seen a tick box which if unticked (pptp) the unit doesnt do anything with vpn traffic but can't seem to find any options anywhere.

Please can someone help?

This is because the 3.2.3 firmware is missing the option, a later beta firmware has the option but only through telnet.
You can get the beta firmware here:
ftp://ftp.draytek.pl/Seria_2710/Firmware/3.2.6_BETA/

Once you've flashed the newer firmware to it, connect to it through Telnet and in there enter:
vpn remote pptp off
The same goes for ipsec and l2tp in place of pptp in there

That should allow your VPN to work normally

It is case sensitive so you need to ensure you type

vpn remote PPTP off
vpn remote IPSec off
vpn remote L2TP off

Many thanks for replying