Score:0

Ubuntu cannot reconnect to Port using Telnet after a network disconnect

ng flag
Ken

I have a server running ubuntu 18.04 and we use a clients data through a specified IP/host.

to test the connection we use the telnet command.

I was able to connect to this with no issues. upon disconnection and reconnection of our server from the network we could no longer connect. we spoke with the network managers and the handshake can be seen sent from our server, to the end user and sent back through the clients firewall to our server. our server at this point never acknowledges. the same happened when the Network manager opened the rules to allow a ping (this has been closed now)

I have connected a windows machine to the same port in the switch and changed the windows IP to match the disconnected Ubunto IP and telnet works (same with ping when the rules were changed to allow this). all of this is suggesting the issue is local to our server but I am scratching my head to what could be causing this.

ufw shows inactive.

Any help would be greatly appreciated.

James S. avatar
de flag
What is meant here by "disconnect and reconnect"? Do you mean physically disconnecting the cable? Do you mean rebooting the server? Do you mean disabling the network interface and the re-enabling it with a command? Have you verified that the IP address of the server has not changed? are you able to log into the server and examine its logs and configuration?
Score:0
ng flag
Ken

I have resolved. My Ubuntu machine had a second interface set up (to receive data from a separate switch and network) we found that somehow it was getting lost on its way back. I removed that interface from my netcfg and moved that functionality to a different server and this seemed to address the issue.

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