Common port numbers need to be memorized by anyone who is looking to work in tech. Once you start working in tech you will memorize these port numbers just because you have to work with them all the time. However, if you are looking to get your foot in the tech industry, having these port…
SSH is the secure shell protocol used to securely exchange data between to computers. SCP is the secure copy protocol used to securely copy files from one computer to another. SCP uses the SSH protocol to make this file transfer possible. The default port for SSH (and SCP) is port 22, however some system administrators…
Internet Protocol Version 6 (IPv6) is the latest way to provide unique addressing to systems within a network. IPv6 is slowing replacing IPv4 IP addresses. (Note, there is no IPv5). The main reason that IPv4 needs to be replaced is the huge amount of devices which connect to the Internet cannot be handled by the…
There’s a number of online speed test websites, but they are all intended to test residential connections of less than 100Mb. They are also non standard and reliy among other things on browser speeds. iperf on the other hand is an industry standard open source tool used to test network speeds well beyond 100Mb. Jperf is a GUI front end…
A BGP transit provider will often send their customer a ‘full table.’ A full table is a table of all the routes and prefixes that the transit provider can connect to. This should be a table of all the IP address blocks available on the public Internet. Different transit provider’s ‘full table’ or Internet global routing table…
On a network, link is established when two devices are able to communicate through layer 1 and layer 2 of the OSI Layer model. When link is not established, the two devices involved in the connection are not able to communicate with one another. There are numerous reasons why two devices would not be able to…
IT people have certain types of jargon or words that are not really defined anywhere. “Bouncing a port” or “bouncing an interface” is one such phrase. There is no where to really look up what this means. You can search Google, but the first result I get (experts exchange) is completely wrong. “Bouncing a port”…
Level 3 Communications is a huge network provider. They sell all kinds of networking services, including IP transit, VOIP, and cloud services. Their primary ASN is AS3356. A network as large as Level 3’s is going to suffer outages from time to time. There are a number of tools you can use to see if Level…