- https://linkmeup.ru/blog/11.html
- https://habr.com/ru/post/307252/
- https://kbespalov.medium.com/виртуальные-сетевые-устройства-в-linux-linux-bridge-7e0e887edd01
Register ICMP replies from 10.10.13.38:
$ sudo tcpdump -n -i tun0 -XSs 0 'src 10.10.13.38 and icmp[icmptype]==8'
Add rule to register new (does not watch for related, established) connections to your machine:
$ sudo iptables -A INPUT -p tcp -m state --state NEW -j LOG --log-prefix "IPTables New-Connection: " -i tun0
Check the logs:
$ sudo grep IPTables /var/log/messages
Delete rule:
$ sudo iptables -D INPUT -p tcp -m state --state NEW -j LOG --log-prefix "IPTables New-Connection: " -i tun0
Release the current lease on eth0 and obtain a fresh IP via DHCP in Linux:
$ sudo dhclient -v -r eth0
$ sudo dhclient -v eth0
- https://www.booleanworld.com/depth-guide-iptables-linux-firewall/
- https://habr.com/ru/sandbox/18975/
List rules in all chains (default table is filter, there are mangle, nat and raw tables beside it):
$ sudo iptables -L -n --line-numbers [-t filter]
Print rules for all chains (for a specific chains):
$ sudo iptables -S [INPUT [1]]
/etc/fail2ban/filter.d- filters which turn into user-defined fail2ban iptables rules (automatically).
Status:
$ sudo service fail2ban status
$ sudo fail2ban-client status
$ sudo fail2ban-client status sshd
Unban:
$ sudo fail2ban-client unban --all
$ sudo fail2ban-client set sshd unbanip <IP>