Knowledge Base

Destination Address Unreachable with dial-up modem

Question

I have both a cable modem (ethernet interface) and dialup connection. PingPlotter works great on the cable modem connection but I can't get it to work on a dial up connection. I know it's working because I can browse the net with my browser but Ping Plotter just gives me a "Destination Address Unreachable" message when I try to use it. Can you tell me how to get Ping Plotter to work on a dialup connection?

Solution

There are a several possiblities here, the most likely two being:

• Your dial-up ISP is blocking ICMP echo requests. This is a crucial player in traceroute and without it, there's no way to get PingPlotter (or Ping, or TRACERT) to work. They may also be blocking ICMP echo replies and ICMP TTL Expired packets. Your best bet here is to contact your ISP and ask them if this is the case (and what you can do to change this behavior).
• You may have a firewall of some kind set up, which is filtering packets from your modem, but not for your broadband connection. Firewalls often block ICMP - and you may have to enable ICMP functionality for PingPlotter to work. Popular firewalls are Zone Alarm, Symantec Internet Security, and the built-in Windows internet firewall.