Mar 20 2012

Configure Port-Knocking in RouterOS.

Port knocking is a method of establishing a connection to a networked device that has no open ports.

Before a connection is established, ports are opened using a port knock sequence, which is a series of connection attempts to closed ports.
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Nov 17 2011

Linux Reverse Path Filtering (IPv4)

By default routers “route” everything, even packets which ‘obviously’ don’t belong on your network. A common example is private IP space escaping onto the Internet.
Lots of people want to turn this feature off, the method is called “Reverse Path Filtering”.
Basically, if the reply to a packet wouldn’t go out the interface this packet came in, this is a bogus packet and should be ignored.
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