Score:0

RHEL Server Accepts Telnet from all Clients Except a Rocky Linux VM

cn flag

I have a few VMs on a XenServer. One is a RHEL 8.7 running SSH server. Another is a Rocky Linux 8 client and also some other Ubuntu and Windows systems. The Ubuntu and Windows systems can telnet to the RHEL server just fine. The Rocky VM cannot. All static IPs with firewalls disabled. The Rocky system can ping the RHEL machine but not telnet. It just says "Trying " and then fails after a couple minutes stating "Connection timed out"

Any suggestions? Any log files I can check?

Thanks!

Romeo Ninov avatar
in flag
Telnet or `ssh`? Because these protocols are different!
techguy817 avatar
cn flag
Trying to telnet. Telnet <IP address>.
Romeo Ninov avatar
in flag
Is it telnet server started on the target machine? Have you try from Rocky `nc <IP> 23`?
techguy817 avatar
cn flag
The telnet server is started on the target RHEL machine. Again I can connect just fine from Ubuntu and Windows clients using telnet. Result of `nc <IP address> 23` is also "Connection timed out" This Rocky VM is able to telnet to google.com 80 just fine though.
Romeo Ninov avatar
in flag
Have you try to `ssh` from Rocky to target? And just check again the firewalls on Rocky and target
techguy817 avatar
cn flag
'ssh <IP address>' fails with 'Connection timed out' on Rocky Linux to RHEL. I have run 'systemctl stop firewalld' on both machines.
Romeo Ninov avatar
in flag
Are they connected to the same IP network, same netmask, have same default gateway set. And are they connected to the same virtual switch in XEN?
techguy817 avatar
cn flag
Same IP network and same gateway set. All on the same network segment so shouldn't need to reach out to the gateway. Really strange...
Romeo Ninov avatar
in flag
Please check again in XEN if they are attached to the same virtual switch (or whatever it is named) and if you do not have there some filters
techguy817 avatar
cn flag
Yes it is all the same VM network. I am able to ping from the Rocky Linux client to the RHEL server just fine.
techguy817 avatar
cn flag
Not sure if it helps but if I do 'telnet <IP> 80' it immediately comes back 'Connection Refused' vs the timeout if I use another port like the default.
techguy817 avatar
cn flag
Let us [continue this discussion in chat](https://chat.stackexchange.com/rooms/147604/discussion-between-techguy817-and-romeo-ninov).
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