by Tony Mattke on April 19, 2010
Netcat or nc, is a forgotten tool in too many arsenals these days. It lays dormant waiting at the command line to make connections across the globe for you. Knowing how to use it, could ease many of your day to day tasks. Simply put, netcat creates a TCP socket either in listening mode (server) or a socket that is used to connect to a server (client).
One of the simplest examples is to use it for a chat server / client. Lets assume were starting the server on a host with an ip address of 198.19.6.8 and were going to use port 8888. The following example allows us to setup a connection between the two hosts and type messages back and forth using stdin.
server:~$ nc -lp 8888
... in a subnet far far away
client:~$ nc 198.19.6.8 8888
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by Tony Mattke on August 10, 2009
For some, BGP is a rather large obtrusive beast of a protocol that scares them half to death. This is not without good reason as BGP is not only the most important protocol running on your network, but it is also one of the most targeted routing protocols in terms of malicious attacks. The majority of BGP attacks are based around the pretense of flooding your network with false prefixes to direct interesting traffic to destinations where the traffic can be sniffed / recorded.
The following tips are simple measure to help mitigate against such nasty things.
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by Tony Mattke on May 14, 2009
One of the things I used to deploy frequently at my previous position was transport for other ISPs and businesses. Since MPLS support is in its infancy on the Imagestream platform, and was yet to be deployed at the time, this is what I came up with. The configuration is quite simple, setup an OpenVPN tunnel across your network, and bridge a vlan or interface to it. Simple, right?
Here is one side of the config…
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