| Firewall Rules |
|
| Example Firewall Scripts |
|
| General Firewall Rules |
- Turn on ingress and egress Rules
- Turn on/off various /proc options
- Outgoing Rules
Allow all internal PCs to freely access the Internet
- Incoming Rules
Allow incoming DNS requests to the DNS server
Allow incoming SMTP requests to the mail server
Allow incoming HTTP requests to the web server
Allow incoming FTP requests to the ftp server
Allow incoming ssh requests to the ssh server
Allow incoming wireless requests to the wireless gw server
Allow incoming ppp requests to the ppp gw server
Allow incoming secure pop3/imap requests to the secure pop server
Allow incoming authenticated vpn requests to the vpn server
Disallow messenger.msn.com
Disallow oscar.aol.com
Disallow messenger.yahoo.com (IIRC)
|
| NAT Rules |
|
| IP Masquerade |
|
| Egress and Ingress Filtering |
- Ingress Filtering: incoming network traffic entering your LAN
IETF.org RFC2827.txt
Sans.org Packet_filter - ingress/egress
Sans.org Firewall Issues
- Egress Filtering: outoging network traffic leaving your LAN
Sans.org Top Ten Blocking Recommendations Using IPChains
Sans.org ipchains Egress Rules
Sans.org Egress Filtering - cisco
Sans.org Egress Filtering ( same as above )
Incidents.org Egress - cicso
|
| Cisco ACLs |
|
| Proxy Server Rules |
|