We have 3 PortServers in our SCO UNIX environment, and we get sporadic SYN_SENT connections which do not clear quickly so please advise what can be done to correct the problem?

Serial Servers & Infrastructure Mangement Portserver TS
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Hello,
We have 3 PortServers in our SCO UNIX environment which at time show connections ESTABLISHED and everything appears to run properly.
However at times we get sporadic SYN_SENT connections, which hang up processing and they do not clear quickly so please advise on what can be done to diagnose and correct the problem.
Regards,
Mark

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Hello @marklboucher . The SCO Realport driver hasn’t been supported for a few years, for instance the SCO Unix 6.0 driver was last released on 7/29/2005. The SCO 5.0.x driver would be older than that so this isn’t something we’d likely be able to assist with.

Doing a search in google, it looks like SYN_SENT was mentioned in some SCO release notes here:

The following article also came up in the search, which indicates this may be a network-related error response: What means SYN_SENT status in a socket? | by José Castro | Devsys | Medium

Our current Terminal Server product line is the Digi Connect EZ products, and we only support certain builds of Windows and Linux at this point. You can see the Release Notes from this link, if you’d like to look into our modern productline:
https://www.digi.com/products/networking/infrastructure-management/serial-connectivity/terminal-servers/digi-connect-ez-16-32
https://hub.digi.com/support/products/infrastructure-management/digi-connect-ez-16-32/

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If the connection is interrupted, but the serial server does not detect the interruption to allow a new connection, you can activate RealPort keep alive and tweak the settings to have the serial server detecting the disconnection faster and freeing up resources to allow for a new connection faster:
To enable RealPort keep-alives on a PortServer TS device, you can use the command setting rpkeepalives=on. RealPort keep-alives are messages sent approximately every 10 seconds within the RealPort protocol to indicate that the connection is still alive. This setting can be turned on or off depending on your needs. Note that RealPort keep-alives generate additional traffic compared to TCP keep-alives, so consider your network environment when enabling this feature.

For example, you can set it by entering the command:

set config rpkeepalives=on

This will enable RealPort keep-alives. If you want to save this configuration so it persists after reboot, ensure the save option is set to on.

For more detailed command usage, you can refer to the Digi One and PortServer TS family command reference here: https://hub.digi.com/dp/path=/support/asset/digi-one-and-portserver-ts-family-command-reference/