Localhost Ncat: Connection refused

Graylog Central (peer support)
1

Hello,

I just set up my Graylog server on AWS, and so far, I can access the WebUI, etc. However, I’m not able to even send a test message to Graylog. I set SELinux (CentOS 7 system) to permissive, I’m not running FirewallD, and my Lightsail firewall is allowing all TCP and UDP traffic my from my home’s IP.

Even when I try to connect from localhost, I get the following message:

echo "Hello Graylog, let's be friends." | nc -w 1 -u 127.0.0.1 9099

Ncat: Connection refused.


2020-08-11T14:54:19.660Z WARN  [ProxiedResource] Unable to call http://glog.mygreatserver.com:9000/api/system/metrics/multiple on node <d74bfe23-e7a3-4c11-85a2-4949820ca5aa>: connect timed out
2020-08-11T14:54:25.662Z WARN  [ProxiedResource] Unable to call http://glog.mygreatserver.com:9000/api/system/metrics/multiple on node <d74bfe23-e7a3-4c11-85a2-4949820ca5aa>: connect timed out
2020-08-11T14:57:40.025Z WARN  [LicenseChecker] License violation - Detected irregular traffic records

I also ran a port scan on the server

Port Scanning host: 23.17.127.191

	 Open TCP Port: 	22     		ssh
	 Open TCP Port: 	111    		sunrpc
	 Open TCP Port: 	9000   		cslistener

I’m not sure what I haven’t configured correctly, so any insights would be greatly appreciated!

2

Can you share more details about your environment? Since you’re sending it to localhost, then I assume you operate on the host where Graylog is running, so it’s not clear why you are referring to some firewalls and home IPs.
First, please show output of
lsof -Pni :9099
(assuming 9099 is your Input port, please share Input configuration also)
Then additionally I would check the following:
iptables-save
ip r
ip -c -br -4 a

3

Hi @zoulja, thanks for the reply.

Sorry for the confusion about the home IP, firewall, etc., I guess I was just trying to clarify my configuration.

I ran lsof -Pni :9099 as you recommended, and there was zero output.

Also, this is a CentOS 7.8 system, and I don’t believe I’m running iptables.

systemctl status iptables

Unit iptables.service could not be found.
4

Port is not listened and you didn’t provide requested information.
The end.

5

CentOS7 by default uses firewalld service, not iptables. So try to check firewalld:
sudo systemctl status firewalld.service

6

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