When I managed our suppliers remote network support connections, development of complex VPN, firewall and NAT setups were required. Centralized VPN concentrators plus small site-to-site VPN devices of mixed origins had to be supported and configuration knowledge to be exchanged. The most common VPN devices were Cisco's smallest PIX 501 and Cisco 831, together with Linux.

Remote VPN Networking with Cisco PIX Firewalls

VPN Network Howto's
Cisco's smallest security appliance PIX 501 is a solid device for building site-to-site IPSEC VPN tunnels with speeds of more then 3 MB/s. Although surpassed by Netscreens 5 series in terms of features and flexibility, it handles standard setups easily. Here we describe a site-to-site VPN tunnel setup with Linux. Although there are some setup descriptions on the net, none covered the secific setup for using NAT on the internal interface, to allow only inbound connections from the Internet to the 'inside' network.

Remote VPN Networking with the Cisco 831 Router

VPN Network Howto's
Introduced at the end of 2002, the Cisco 831 SOHO router is competing with the smaller, faster and easier configurable PIX 501 of Cisco's own making. Altough released one year after the PIX 501, with more then twice the physical size and housed in cheap plastic, are there any advantages? Well, if having a full-fledged Cisco IOS at your fingertips is one, than thats it. We will configure the 831 identical to the PIX site-to-site IPSEC VPN setup with NAT.

IP Subnetting Tables

These pages are quick reference sheets to identify network ranges for IPv4 subnetting. Manual calculation tends to be slow, and cumbersome.

First Hop Redundancy Protocols (FHRP)

This is a quick reference for First Hop Redundancy Protocols (FHRP), including HSRP, VRRP and GLBP.