bookmarks/cheat/network.md

Know your public IP

• curl ifconfig.co
• curl ident.me

Block an IP with iptables

• iptables -A INPUT -s 35.196.128.87 -j DROP

Undo the previous rule

• iptables -D INPUT -s 35.196.128.87 -j DROP

Watching active IP connections on Linux

Sources :

• Joyent Support - (2016) Watching active IP connections - Linux
• Super User
• Server Fault

Incoming connections:

watch -d -n1 lsof -i

Trace all connections on specific port to /var/log/messages (syslog) using iptables :

sudo iptables -I INPUT -p tcp --dport 443 --syn -j LOG --log-prefix "HTTPS SYN: "

Trace all connections on specific port to /var/log/messages (syslog) using iptables :

sudo iptables -I INPUT -p tcp --match multiport --dports 443,636,389,8095,80 --syn -j LOG --log-prefix "HTTPS SYN: "