Saturday, April 26, 2003

OpenBSD IPsec clients
This page is for people who wants to use IPsec clients with OpenBSD as an IPsec gateway.

Thursday, April 24, 2003

A technique for counting NATted hosts
A PDF file.
Detecting NAT Devices using sFlow
Unauthorized NAT (Network Address Translation) devices can be a significant security problem. Typically the NAT device will appear to the network administrator as an end host and it will authenticate itself onto the network. However, the NAT device provides unrestricted access to any number of hosts connecting to it directly, or more troublingly via wireless (Wi-Fi 802.11). Wi-Fi is a particular problem since it allows access to the network from a considerable distance, allowing unauthorized access without even entering the building.
Reliably detecting NAT devices is difficult since they are virtually indistinguishable from legitimate hosts. This paper describes how the detailed, pervasive, traffic monitoring capabilities of sFlow (RFC 3176) can be used to identify NAT devices on a network.