> My question is, why? Since that is a machine controlled by your ISP, they can do whatever they want or do not want. Do not believe all ISP are respecting Internet standards. Are there standards? Maybe it is a mistake in configuration. If I remember correctly from some time ago when I read tcp/ip illustrated but not, some kind of ARP server can be set up, maybe bridge related, but i'm not totally sure.
So, try to bug your ISP with that ARP overwrite.
