Archives: 2008 February

Each TCP device on a network has an associated ‘ceiling’ on TCP Data Size, called the MSS (Maximum Segment Size). The TCP MSS is negotiated between two communicating devices via the TCP SYN and SYN-ACK packets. After this negotiation, each TCP device must comply with the advertised MSS of the peer device, and should not [...]

This post discusses the most basic steps needed to troubleshoot a LAN-to-LAN IPSEC tunnel between Cisco Routers. A Cisco Router with the proper IOS version can make an excellent IPSEC VPN termination device, and can be used to securely connect two distant LANs over an untrusted network, such as the Internet. In our example below, we [...]

1. Nessus DOWNLOAD Nessus is a Network Vulnerability Scanner tool based on a client-server model. It features high speed discovery, configuration auditing, asset profiling, and vulnerability analysis of your network and systems. It is constantly updated with more than 11,000 plugins for the free version. Every audit in Nessus is coded as a plugin : [...]

1. PuTTY for SSH Access DOWNLOAD PuTTY is a Secure Shell (SSH) client that runs on Windows. You can use PuTTY to access remote network devices (Routers, switches, firewalls, Unix Servers etc) using the secure SSH protocol. With an increased emphasis on security, most network devices can now be remotely accessed via SSH. PuTTY supports [...]

One of the most popular firewall products for the small business market is the Cisco PIX 501. Out of the box it requires just a few configuration entries and you are up and running. In this guide, we will walk through the steps for configuring your brand new pix at the network edge. This guide [...]

Please Do Not Throw Sausage Pizza Away !!! You might be wondering what I am talking about, but take a closer look at the Red letters above…Yes you are right, these are the first letters of the 7 Layers of the OSI Model, the fundamental building block of TCP/IP Networks. The 7 Layers of the [...]