Simon PainterSomewhere to keep things

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. The 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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