Can't Access Router Settings via 192.168.2.1

I have recently changed modem/routers as my connection speed was increased recently and the old modem wasn't up to the task... The previous modem/router was preconfigured and I did nothing to it, however the new one requires settings be fixed by accessing it via a browser at 192.168.2.1

When the technician came to check my line and set up the new modem, we encountered a strange situation. Despite being connected by Ethernet cable, my machine could not access the IP address reserved for the router.

The reply is: "Safari can’t connect to the server.
Safari can’t open the page “ http://192.168.2.1/” because Safari can’t connect to the server “192.168.2.1”."

We tried Firefox and the same happened.

I have deactivated my firewall, rebooted, changed cables, restarted the router, got Safari to pretend to be Explorer, got the neighbor's dog to bark at it, everything except make a blood pact with the devil, and the two browsers on my machine think that 192.168.2.1 is an external address- which it isn't, and of course fails to connect.

The technician used his laptop to configure the thing, so I can access the internet (obviously) but I must find out why I can't access the router/modem's settings, if only to find some logical reason for this illogical behavior.

I've tried looking this issue up, and I get lots of bad wiring, wireless connection, windows proprietary shenanigans, but none that explain my situation.

I'd appreciate it if someone could help me make sense of this.

My setup:

Computer Model Name: Power Mac G4 (AGP graphics)
Model Identifier: PowerMac3,1
Processor Name: PowerPC G4 (3.3)
Processor Speed: 1.35 GHz
Number Of CPUs: 1
L2 Cache (per CPU): 256 KB
L3 Cache (per CPU): 2 MB
Memory: 832 MB
Bus Speed: 100 MHz
Boot ROM Version: 4.2.8f1
Sales Order Number: M7827LL/A

Router: "2-Wire Gateway"