Subnet Toolsand other network tips

Security

Getting your underpants inside out over NAT

A colleague asked me to write a post on NAT and so this one is for him. I’m going to use a very basic three router lab to go through the common types of NAT and where they are used. First off there is the convention of inside and outside interfaces.┬áThe golden rule here is […]

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Logical look at masks

Having done an introduction to wildcard masks and the cool things you can do with them I thought it might be worth writing about the logic behind both subnet masks and wildcard masks. Masks use two of the most basic logical functions that computers can perform, a logical AND and a logical OR. Logical AND […]

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Getting Wild[card masks]

If you ask most people what a wildcard mask is they’ll probably say it’s an inverse subnet mask. That is a massive under-representation of the power of a wildcard mask and does not do fair justice to the range of useful tricks you can do with a wildcard mask. We’ll start with why people think […]

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Stats on concurrent SSL VPN sessions.

In the past I always used ‘sh cry is sa’ to give me a view of the number of concurrent VPN sessions on an ASA. I am involved in an Anyconnect SSL VPN roll out and today I was asked to pull off stats on how many users are connected to each solution. The following […]

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