I have read a handful of posts say this can and cannot be done. From my
testing here in our lab, I am unable to get this work - using Microsoft's
VPN client behind Novell's NAT and BM - authentication fails with the MS 721
error, which is a problem with GRE and we have verified that GRE is never
getting to the VPN server. As a side note, we are running BM v3.6 and NAT
is at v6.00j

So what is the official word with using the MS VPN client behind Novell's
NAT - I guess more specifically, the issues with GRE? Also... don't say it
is a GRE issue with NAT in general, because that is not true - I have been
able to verify in more than one setup that GRE can be passed through a
router using NAT ( one was a Netgear firewall and one was a 3Com firewall )
using MS VPN client - the only scenario I cannot connect through is when I
am behind Novell.

Also, I found a previous post that suggested opening up port filters - TCP
1723, UPD 1723, UDP 53 ( though this one isn't required ), and Protocol 47
( which would be GRE ) - this didn't work either.

Thanks in advance for any info you could provide.... I find it frustrating
that behind a Novell server is the only place that I cannot connect to a VPN
server using MS VPN client...