Building a Linux firewall

Nov 29 01:54:37 deathstar kernel: Deny TCP 20.2.51.2:1039 20.2.51.105:23
Nov 29 01:54:42 deathstar kernel: Deny TCP 20.2.51.2:1039 20.2.51.105:23
Nov 29 01:54:53 deathstar kernel: Accept TCP 192.168.1.2:2598 20.2.51.2:23
Nov 29 01:54:53 deathstar kernel: Accept TCP 20.2.51.2:23 192.168.1.2:2598
Nov 29 01:54:53 deathstar kernel: Accept TCP 192.168.1.2:2598 20.2.51.2:23