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Client and server are in the same subnet (in the same VPC, in the same account), and inbound & outbound 5280/tcp & 5281/tcp are allowed in the security group.
Are there any ACLs associated with either instance?
Which operating system are the EC2s running, and is there a host-based firewall running on either? This would be likely be ufw
on Ubuntu, or firewalld
on Fedora/RHEL/CentOS.
Confirm the licence manager is definitely running and listening on those port(s), check with netstat -tulpn
.
ncat
https://nmap.org/ncat/guide/index.html can be useful for troubleshooting port issues, the package should be available to install from the standard repos and I believe is part of the nmap
package (Ubuntu) or nmap-ncat
(Fedora/RHEL/CentOS).
Hi, did you validate that the additional status checks of your various instances made by EC2 supervision are "full green"?
See https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/monitoring-system-instance-status-check.html
In particular, the system status check (see doc section) validates network connectivity. You should make sure that you're good on this side.
The next steps that I would suggest :
- extends your current security groups to allow ICMP protocol to test via ping between server and clients
- finally try to connect via telnet between clients and server to see if you get the proper connection or more diagnosis / debugging info.
I personally often use telnet to debug my tcp connectivity issues: see https://netbeez.net/blog/telnet-to-test-connectivity-to-tcp/
Hope it helps Didier
Hi Didier, thank you for the response and the suggested telnet debug. It turned out that it was the host-os/firewalld being enabled, while I was assuming was disabled and this issue handled by AWS Security Group policies exclusively...
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thanks for the direction RWC, indeed - It turned out that it was the host-os/firewalld being enabled, while I was assuming was disabled and this issue handled by AWS Security Group policies exclusively...