Can you help me set up my router?

Question

DHCP

We have a wonderful provider in Voronezh, I had a chance to set up a router for it to access the Internet in a shopping center.
There is no authorization, neither by poppy, nor pptp / l2tp - you just insert the cord. DHCP distributes the address and the Internet seems to be in the hands, but.
Everything works only on a computer / beech. the router does not want to work. and I understand it)
and the problem in my opinion is that DHCP gives the mask 255.255.255.255
while the gateway address and the issued dynamic address are in completely different subnets
, for example:
address 91.219.5.xx
gateway 91.209.124.6,
respectively, when trying to send where any package get that "network unrechable"
if we prescribe the address and everything else as static and the mask 255.0.0.0, then everything works until the lease expires and a new address is issued.
Are there any options to make friends with the router with the Internet?
I see only one so far - buy static and stupidly score with a normal mask.
ps: D-link Dir 300 NRU B5 router, tried to play with the firmware, but it did not bring anything. I did not change it into kinetics. stopped at the latest available beta

Answer 1

Yes, it's funny. Why does the computer work? In this case, you should also write network unreachable. Maybe the ethernet is somehow configured in PtP mode? Try to show ifconfig/route from a working laptop. Well, you can also look at a couple of pings with tcpdump on a clean (quiet) grid and copy them here.

Answer 2

This is most likely the so-called IPoE, IP binding / issuing goes to the port of the node in the house, and not to the hardware on the user's side. Why the router receives a /32 mask, and the computer is a friend, I have no idea, I'm not sure that it is generally possible to somehow distinguish. Maybe a bug in the firmware of the router itself?
But in general, the logical solution is to put openwrt / ddwrt on the router, get the address, and then automatically change the mask to the desired one with a self-written script.