[Dx4win] Staying Connected to TELNET

[Larry Alkoff]

On Mon, 4 Nov 2002 21:05:25 -0800, STU wrote:

>Is there anyone out there that has a hard time staying connected to TELNET.
>I have a high speed cable connection that works great for the Internet. No
>problems!
>When connecting to a DX cluster via TELNET (with DX4WIN) and the activity is
>somewhat slow, I seem to get disconnected. During peak times such as
>contests I stay connected just fine. I understand there is a so called "keep
>alive" option either in DX4WIN or some other outside source. The idea is to
>keep the traffic moving. If windows isn't seeing any traffic from you, (some
>ISP's as well.) disconnect you so others can use the IP you were on. Is
>there a setting in DX4WIN using the TCP/IP setting with this so called "keep
>alive" feature? Please advise. TNX, 73 STU
>
>Please respond to: w6yyy@arrl.net
>


I have noticed that normally I lose my connection in about an hour.

My experiments indicate that the reason is that somehow Telnet attracts
a swarm of attempted connections from various unknown urls that overload the ability of
Telnet to keep itself alive.

Various methods of sending "keep alive" signals have made no difference.

I maintain two machines - one is Linux.  If I establish a Telnet connection under DX4Win
and set the Linux machine to monitor connections using "tcpdump" which is included in most
Linux distributions, I can clearly see the attempted connections building up - to as many as hundreds per second!

This is a classic DOS (Denial of Service) attack.  Most people would be unaware of the attack
unless they are running an analysis tool like tcpdump.

I've tried nearly a dozen different Telnet sites - the result has always been the same.
That is why I'm looking for a good http site that does automatic refreshes.

My connection is a 24 hour cablemodem (Time-Warner of Austin TX RoadRunner)
and I think that kind of connection is attractive to the kind of people doing this.
They can easily tell it's Time-Warner from the first few digits of the IP address.

Many have complained about the difficulty of keeping their Telnet connection "up".  
Hope this information helps others.

Larry Alkoff N2LA



Larry Alkoff N2LA - Austin TX