I have Redhat 7.0, with a DSL modem connected. This Linux box serves the Internet to my home network. I used to to be able to telnet to my machines at work, from the Linux box, or any box on my network. Now, this now longer works, giving "Connection closed by foreign host". I have changed nothing on my end, I can telenet to work if I use a dialup modem, so work machines are OK, and ISP says nothing changed on their end and no ports are blocked. So who is telling the lie here? Connection to the internet works fine, just cannot telnet.

Any clues would be most appreciated.

I can't get a clear picture of ur problem especially ur home network & work network ...

Pls explain ..

Kias

Check with you DSL service providers again.
Ask them if you have a static or dynamic IP address associated with your machine connected to the DSL modem.
When I installed DSL in my shop we had to use DHCP in order to get all our internal nodes to use the DSL modem. Unless you have a static IP address associated with the computer directly connected to you DSL modem, you may be having DHCP problems.

My guess would be that your ISP is the problem on thier end.

You are right. Turns out my ISP uploaded new firmware to my DSL modem, without telling me. This is when telnet stopped working. Took a while to discover this. By using tcpdump, we determinined the DSL modem was listening on a different IP address. Once we added a route to this address, telnet started working. Not sure I have all the story correct here, had a friend helping me. I am running ipchains, and have a dynamic IP address from my ISP, and not really sure if I am running DHCP or not. Thanks for your relply.

Excellent.
Glad to help.