OK I was partly checking in case it was something like FTP where there the ports for the data connection are dynamically chosen
in addition to port 21 that most people would see listed in how-tos.
That kind of service was made when it was assumed there is already a true end-to-end connection without stuff like NAT to get in the way,
If it is just one port and the computer is accepting connections when on one of the routers I think we are safe to assume the computer side of things shouldn't need further changes.
So for the Xilo one we only need to consider the router and the ISP side of things (much as you have been doing).
1) With the computer hooked up for the Xilo connection, check the public IP using something like the
TBB tool and confirm this is the same as what you have been giving out as the IP for the others to connect to
2) check your router firewall
DGN1000 (having checked the
user manual) has a similar interface to many Netgear (Home) products when it comes to configuring rules, including my old and common DG834G
The basics:
First define a
service, which specifies a port number (7755) and whether it is TCP, UDP or both (try both if not sure)
Second define an
incoming rule, which specifies the service you are allowing, which WAN addresses are allowed in (the public IPs of the other people you want to allow to connect), the LAN address of the computer to forward to, whether to allow or block and whether to log.
To set that up you may want to initially choose Allow Always and Log Always or Match (so you can check the log to see if the router sees the incoming requests)
Note if the other people connecting do not have static public IPs you will either have to allow all WAN addresses or large ranges based on the block the ISP gives out (if you have heard of RIPE you can ask your other persons for their current IPs and find their ISP ranges there, otherwise it is going to be Allow All).
Thirdly this model also supports reserved LAN IP addresses so you can add an entry for the computer to ensure it is always given the same LAN IP from the Netgear as you need that for the incoming rule, while leaving the computer IP settings on Auto so you can connect it to either router without keeping changing things by hand.
EDIT: (I originally asked if you had enabled uPnP but reading again I see you have. I have revised the section below)
I don't know if
that game does use uPnP to request ports opening automatically (it's something I only use if I trust all the computers / software on
my LAN). You can still check the
UPnP Portmap Table from time to time to see
if anything is actually using it
prompt $P - Invalid drive specification - Abort, Retry, Fail? $G
prlzx on n e w n e t: ADSL2+ / 21CN at 3.5Mbps / 800kbps
Edited by prlzx (Tue 28-Aug-12 00:58:44)