Greetings,
Looking for a little help with ipfwadm. Got a good machine running 2.0,
two nics and the system is passing traffic wonderfully. Now I would like
to put in packet filtering. IPFW sounds as though it will fit the bill.
The HOWTO regarding IPFW suggests a script, which I have written and is
below. The problem, when I execute the script nothing comes in, nothing
goes out, the perfect firewall. The bad news is I need some traffic to
pass. The network behind the firewall is a subnet of a class B network with
255 addresses. If you have any insight on why I might be running into
trouble, or if you have suggestions, I would love to hear from you.
#!/bin/sh
# Setup IP packet Accounting and Forwarding
#
#
# By Default DENY ALL services first
ipfwadm -F -p deny
#
# Flush all Commands
ipfwadm -F -f
ipfwadm -I -f
ipfwadm -O -f
#
# Allow email to NCTAMS01
ipfwadm -F -a accept -b -P tcp -S 0.0.0.0/0 1024:65535 -D 111.229.13.13
# Allow email to NS1 Relay host
ipfwadm -F -a accept -b -P tcp -S 0.0.0.0/0 1024:65535 -D 111.229.13.2
# Allow email to outside mail severs from NCTAMS01
ipfwadm -F -a accept -b -P tcp -S 111.229.13.13 25 -D 0.0.0.0/0 1024:65535
# Allow email to ouside mail servers from NS1
ipfwadm -F -a accept -b -P tcp -S 111.229.13.2 25 -D 0.0.0.0/0 1024:65535
# Allow DNS traffic to NS1
ipfwadm -F -a accept -b -P udp -S 0.0.0.0/0 53 -D 111.229.13.2
ipfwadm -F -a accept -b -P tcp -S 0.0.0.0/0 53 -D 111.229.13.2
ipfwadm -F -a accept -b -P tcp -S 111.229.232.0/24 82 -D 111.229.13.2
# Allow Web connections to outside Web Servers
ipfwadm -F -a accept -b -P tcp -S 111.229.13.0/24 80 -D 0.0.0.0/0 1024:65535
# Allow FTP connection to outside Servers
ipfwadm -F -a accept -b -P tcp -S 111.229.13.0/24 20 -D 0.0.0.0/0 1024:65535
ipfwadm -F -a accept -b -P tcp -S 111.229.13.0/24 21 -D 0.0.0.0/0 1024:65535
# Allow Telnet connections to outside Servers
ipfwadm -F -a accept -b -P tcp -S 111.229.13.0/24 23 -D 0.0.0.0/0 1024:65535
# Allow NTP time to NS1
ipfwadm -F -a accept -b -P tcp -S 111.229.13.2 123 -D 0.0.0.0/0 1024:65535
Anthony Landreneau
Network Administrator
Infinity Data Systems
New Orleans Louisiana
(504)455-8973
