[Ubermik]

Thats the point tho, they never DO leave the router in the first place because it IS a router so it doesnt even bother sending them to the modem because the gateway is incorrect

The PC nor the modem looks at the routing information so even with an incorrect gateway packets flow as freely as guiness on st patricks day


So yes IF the router would send the packets to the modem they WOULD be forwarded as they are from the PC, they would have an extra layer of information wrapped onto them by the router compared to the same packet from the PC, but to the modem thats irrelevant as it just sends whatever its sent to the telewest router and lets that sort it out, but the "IF" is the critical word there as they arent sent to the modem, they never get to the wan side of the router to begin with so the modem cant forward packets it hasnt been sent to begin with no matter how good a modem it might be


"I tried an assortment of gateway addresses in the same subnet as the correct gateway address and got the same result with 2 routers and 1 pc the routers I used btw where and old cisco 4000 series and a draytek 3300"

But all other locations bar the actual gateway in that subnet will be a PC and WILL be obtainable without any routing being needed BECAUSE they are on the same subnet

So they will reach someone elses PC and be discarded

The difference with the ACTUAL fault is that the gateway address ISNT on the same network, so it DOES neet to be routed and despite having the wrong IP for the gateway is automatically sent to the actual gateway for that subnet merely because its not for a local destination on that subnet

Thats why you werent getting any joy

Try entering any other gateway from any other Telewest subnet you can find and see what happens then, because its not on the same subnet as your PC it should then be sent automatically to the correct gateway by telewests router

Infact in theory the same might happen with any real world IP that isnt on the same subnet as the host, similar to a two status rule

1. If the final destination is on the same subnet send it to the destination
2. if its not on the same subnet send it to the gateway

For rule two tho the packets gateway information is irrelevant as the telewest router already knows its own gateway to begin with so it just peels off the incorect jacket applied on the PC and possibly reapplied by the modem and then replaces it with an acurate one

The same would happen if the residential gateway/router just forwarded the packets knowing they were wrong but that is where the problem lies, they dont even try

Hence there being no internet connection with the router inline but perfect internet connectivity when connected directly to the modem

Which then leads the telewest support staff to claim its a router problem and therefore isnt supported which is how it sort of looks but isnt as the router is working within the rules of subnetting and is acting as it should do