Re: network issue

[Joe <joe@jretrading.com>]

On Thu, 16 Oct 2025 15:28:53 -0400
"Roy J. Tellason, Sr." <roy@rtellason.com> wrote:

> This isn't strictly debian-related,  so if there's a better place for
> this feel free to point me at it and I'll try there...
> 
> Back when my LAN was a workstation and a DSL modem,  and a bit later
> on a routher/firewall was added,  and a server,   then later on a
> second workstation.  Wifi was an old (now older and very flaky) AP.
> These days wifi is also provided by the "modem" (Hugesnet,  who is
> completely useless for help on this) and it's dual band and seems
> overall faster.
> 
> The problem is when I'm using that wifi I have no access to my local
> server,  I can only get to it by way of the old flaky AP that's
> internal to the LAN.
> 
> Particulars:  The "modem" is 192.168.1.1,  the WAN side of the router
> is 192.168.1.2,  the server on the other side of the router is
> 192.168.0.1,  and the workstations get DHCP addresses assigned when
> they connect,  as do any devices (a couple of phones and a tablet)
> that connect to the wifi.  Is there any simple way to get that
> external wifi to point to my internal server when a 192.168.x.x
> address is used?
> 
> 

Yes, but it may be a bit involved. Firstly the firewall must be opened
to allow the ports you want to use on the server to pass inward through
the router if it isn't using NAT.

If the router is doing NAT it will be necessary to create port
forwarding rules in the router to direct those ports to the server's IP
address. This should automatically create the right firewall rules.

If the router does not do NAT, the modem will need to be given an
additional route, telling it that the route to network 192.168.0.0 is
via the gateway 192.168.1.2.

Finally, if NAT is used on the router, you will need to address the
server as if it was the router i.e. 192.168.1.2 and if not, then use
the server's own IP address.

It all depends on whether the router is just a plain router, or whether
it is using NAT. Your use of the term 'WAN' suggests it is a cable
router, using NAT by default.

-- 
Joe