TCP/IP Part 3

This is another installment in my series of blog posts on TCP/IP based on the Infinite Skills course I have been studying. Last time I did look at ICMP and there is something called ICMP attacks. One method is to flood a server with large files coming from lots of remote hosts and of course you put some kind of virus on these hosts and hijack their connection. Another kind of attack called smurfing is to send a message to every host on a large network and getting them to flood the server with data. Most networks nowadays have hardware that can deal with these kinds of attacks so they are very rare but at one time they were quite common. In sending a message over a network there is something called a 3 way handshake. With this the sending host sends a synchronize request then the receiving host sends an acknowledge request then the sending host sends a get request followed by the data. There is an option particularly on wireless networks as to whether you want the file fragmented and you should select yes unless there is a very good reason not to because more often than not if the file exceeds a certain size it won't get sent and will be returned to the sender. There are thousands of ports on a computer and these are channels not actual ports and it is often a good idea to at least close certain ones of these and monitor which ones your computer is using as viruses can gain access to your computer or network via these. There is a UDP or user datagram protocol which is relatively high speed and is useful if the sequence something is sent in is unimportant. DNS is domain name server and refers to the internet address of a server on a network. HTTP or hypertext transfer protocol is also very similar. The session layer in the OSI model as well as other things replaces lost data if it's retrievable if it's lost in transit on a network. Encryption is also on this layer. Checksum checks a file for its size both before and after it's sent on a network and gives an error message if both aren't the same size. The RTS protocol is used to stream video and audio. If something is encrypted and sent on a network the sending host will normally send an SSL or secure socket layer and the receiving host will reply with a TLS or transport layer security signal.