Keep alive settings on DX Cluster

[NN7M]

Tom,

I use Hamalert for dx cluster spots from hamalert.org. I noticed the connection resets every few minutes. This is constant, so I asked about it on Hamalert forums. Here's what Manuel HB9DQM said:

I can reproduce this issue with RUMlogNG on my Mac. Analyzing the network packets with tcpdump, I found that RUMlogNG actively closes the connection and then immediately reconnects if it has not received any spots for exactly 210 seconds. Given that HamAlert pre-filters the spots (unlike regular DX clusters), it’s quite common to not have any spots for more than those 3½ minutes. Also, the TCP keepalives that I implemented to appease firewalls and NAT engines that like to terminate idle connections (see [Sometimes not receving alerts for a DXCC - #5 by HB9DQM](https://forum.hamalert.org/t/sometimes- ... dxcc/686/5)) do nothing to keep RUMlogNG from disconnecting – it wants to see application layer data.

Perhaps the author of RUMlogNG can make this hard-coded timeout configurable (or add an option for it to be disabled).

https://forum.hamalert.org/t/telnet-ses ... nutes/1311

Based on Manuel's reply, is there a change that can be made to the DX Cluster settings?

Thanks for your consideration,

Ryan NN7M

[DL2RUM]

Such a time out function is not included in RUMlog. For a keep alive check, every 180 seconds a space followed by a linefeed will be sent.

What are the access data for your mentioned telnet cluster?

[NN7M]

telnet address is: hamlet.org
Port is: 7300

My login credential is NN7M. I have a password to log in.

The only three commands that are mentioned are:

sh/dx nn (where nn is the number of last shown spots will be displayed)

set/json (I don't know what this means)

echo foo (command that returns foo -- can be used for keep alive)

[DL2RUM]

telnet address is: hamlet.org

This seems to be wrong, but hamalert.org works.

I've found out that the keep alive check fails. When the server doesn't response, RL assumes a brocken connection and tries to reestablish it.
This mechanism works fine for all telnet dx-cluster but not for HamAlert.

[NN7M]

This seems to be wrong, but hamalert.org works.

Oops, that was my autocorrect trying to be helpful

Could RL send an echo command before the disconnect and reconnect? This would verify the connection is lost or just idle. HamAlert is very useful for getting specific spots.

Thank you,

Ryan.

[DL2RUM]

Any ideas what to sent?
Other cluster installations respond just to a line feed byte.

[NN7M]

echo foo will return foo. If the string is sent from HamAlert the connection is still alive.

If this is not practical how can I keep the connection alive as a RL user?