I have a strong suspicion that my ISP (Charter Communications) has implemented some kind of filtering on my home cable-based (DOCSIS) internet connection. My reception of the RIP44d table broadcase has all but ceased. ip-ip tunnel communication to a friend's machine in a neighboring county only seems to work for a limited time, and only AFTER I initiate a connection from my end. It's as if they're using some kind of NAT or port knocking filter, and only opening the gate for incoming proto 4 traffic for a limited time after I initiate an outgoing request to a specific host.
It is, as Brian N1URO also wrote, an issue in your home router. Other routers have shown this phenomenon for some time. Even when you set a "DMZ" (meaning: forward all unknown traffic to this host), there still is a stateful firewall in place for all protocols except TCP and UDP, requiring you to send outgoing traffic before incoming traffic is accepted.
You will need to have the router put in bridge mode (making it only a modem) and install a better router in front of that. With a suitable router, it can also do the IPIP encapsulation. A Linux system of course is a suitable router as well.
Rob
He can check or dd-wrt or OpenWrt firmware is available for his router as these can forward ipip or can can be set in bridge mode (dd-wrt and OpenWrt are linux based) and much more.
Some firmwares in these consumer routers even don't allow to be put in bridge mode at all. The tabs for it are just missing or they don't have an option for it in their menu.
Bob
On 16-06-06 12:37 PM, Rob Janssen wrote:
(Please trim inclusions from previous messages) _______________________________________________
I have a strong suspicion that my ISP (Charter Communications) has implemented some kind of filtering on my home cable-based (DOCSIS) internet connection. My reception of the RIP44d table broadcase has all but ceased. ip-ip tunnel communication to a friend's machine in a neighboring county only seems to work for a limited time, and only AFTER I initiate a connection from my end. It's as if they're using some kind of NAT or port knocking filter, and only opening the gate for incoming proto 4 traffic for a limited time after I initiate an outgoing request to a specific host.
It is, as Brian N1URO also wrote, an issue in your home router. Other routers have shown this phenomenon for some time. Even when you set a "DMZ" (meaning: forward all unknown traffic to this host), there still is a stateful firewall in place for all protocols except TCP and UDP, requiring you to send outgoing traffic before incoming traffic is accepted.
You will need to have the router put in bridge mode (making it only a modem) and install a better router in front of that. With a suitable router, it can also do the IPIP encapsulation. A Linux system of course is a suitable router as well.
Rob
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Boudewijn (Bob) Tenty -
Rob Janssen