Port 700 blocked
Hello,i need to connect to domain name registrar via EPP protocol which require port 700 opened,no firewalled anywhere.in my Linode i allow ufw port 700 tcp but still i got an error which show still blocked.the error is. "Unexpected closed connection by remote host…"
Please help
3 Replies
hdiep
Linode Staff
I downloaded UFW and was able to open up port 700 as well. Before my rules were active, I had to enable UFW first:
user@localhost:~# sudo ufw allow 700
Rules updated
Rules updated (v6)
user@localhost:~# sudo ufw status
Status: inactive
user@localhost:~# sudo ufw enable
Firewall is active and enabled on system startup
user@localhost:~# sudo ufw status
Status: active
To Action From
-- ------ ----
700 ALLOW Anywhere
700 (v6) ALLOW Anywhere (v6)
When I checked port 700 with nmap, it was showing as closed. Which means that the server or network received the request, but there is no service “listening” on that port. However, a closed port can open up at any time if an application or service is started.
nmap -p 700 $IP_Address
Starting Nmap 7.92 ( https://nmap.org ) at 2023-04-12 13:21 EDT
Nmap scan report for $IP_Address.ip.linodeusercontent.com
Host is up (0.025s latency).
PORT STATE SERVICE
700/tcp closed epp
Nmap done: 1 IP address (1 host up) scanned in 0.41 seconds
Are you seeing your ports as filtered? If so, then a request packet was sent, but the host did not respond and is not listening. This usually means that a request packet was filtered out and/or blocked by a firewall.
If you need some assistance with checking your ports, we have a great guide and community post that could help with adjusting your firewall rules, if needed:
- How do I open a port in my Linode's firewall? | Linode Questions
- How to Configure a Firewall with UFW | Linode
In regards to that error message that you're seeing, I was only able to locate another thread that mentions that they had encountered this error because the server was trying to connect with IPv6. It may be worth checking if that's potentially happening on your end as well.
Hopefully, this information points you in the right direction!
Double-check UFW configuration: Ensure that the UFW rule you added is correct and enabled.
You can list the current UFW rules by running: sudo ufw status verbose
Make sure you see a rule allowing incoming traffic on port 700.
Restart UFW: After making changes to UFW, it's a good idea to restart the firewall to ensure the new rules take effect.
Run: sudo ufw disable
sudo ufw enable
Check the server's network configuration: Verify that there are no other firewalls or security settings on the Linode server that might be blocking port 700.
good luck