Opening the Ports

Ports must be open for Axelar to work: 1317, 26656-26658 и 26660.

You can use the site to check if ports are open: https://www.yougetsignal.com/tools/open-ports/ (enter the IP address - you can see the address here https://api.ipify.org/ and ports in turn 1317, 26656-26658, 26660 all ports with the same IP address)

Or you can find out open ports on the server by entering the command:

ss -tulpn

If your VPS server has a built-in firewall, then you need to open ports 1317, 26656-26658 and 26660.

If there is no built-in firewall, open the ports as described below.

1) UFW (firewall configuration tool) always installed on Ubuntu by default (if not, install: sudo apt install ufw -y). Checking the status:

sudo ufw status

2.1) If in response we receive Status: active - this means the firewall is enabled. We open the ports necessary for Axelar, and prohibit incoming traffic (prohibition of listening to private networks):

sudo ufw allow ssh
sudo ufw allow 22
sudo ufw allow 1317
sudo ufw allow 26656:26658/udp
sudo ufw allow 26660

ufw deny out from any to 10.0.0.0/8
ufw deny out from any to 172.16.0.0/12
ufw deny out from any to 192.168.0.0/16
ufw deny out from any to 169.254.0.0/16

If you want to see the rules that are set:

sudo ufw status verbose

2.2) If the response to the command above is Status: inactive , means the firewall is disabled, there is no protection.

You will most likely have the same answer.

Enter the same as above:

sudo ufw allow 22
sudo ufw allow 1317
sudo ufw allow 26656:26658/udp
sudo ufw allow 26660

ufw deny out from any to 10.0.0.0/8
ufw deny out from any to 172.16.0.0/12
ufw deny out from any to 192.168.0.0/16
ufw deny out from any to 169.254.0.0/16

Checking:

sudo ufw enable
sudo ufw status
ss -tulpn

If you want to see the rules that are set:

sudo ufw status verbose

More information about setting up UFW can be found in the DO's tutorial and here.

Also you can do it differently (with the firewall turned off):

sudo iptables -I INPUT -p tcp --dport 1317 -j ACCEPT

sudo iptables -I INPUT -p tcp --dport 26656:26658 -j ACCEPT

sudo iptables -I INPUT -p tcp --dport 26660 -j ACCEPT

sudo apt-get -y install iptables-persistent

sudo netfilter-persistent save