IP - Internet Protocol prepares a packet (datagram) for transmission across the Internet with the IP header encapsulated. The IP packet is then passed to the next layer where further network information is encapsulated onto it. Internet traffic travel in bursts of segments (packets or datagram) of around 536 bytes (4,288 bits).

The routing table is checked at the router and the process repeats. A packet can be forwarded from router to router. Each one of these steps is called a hops --if a route to the remote host is never found then an error message will return. Routing can be either static or dynamic. Static routing involves manually programming the routing table into the router.

MAC (Media Access Control) manages one of the sublayers handles access to shared media.

MAC address (are 6 bytes long and are controlled by the IEEE). It is a standardized data link layer address that is required for every port or device that connects to a LAN.

Other devices in the network use these addresses to locate specific ports in the network and to create and update routing tables and data structures. MAC address are also known as;

• Hardware address

• MAC-layer address

• Physical address.

• ethernet addre

A MAC layer address look like this: 08:00:05:81:79:66. and it should not be confused with an IP address that look like this: 121.006.62.06 they are not the same and perform different functions.

MAC address can be displayed for Windows NT users by opening a command shell (DOS prompt) and entering ipconfig /all -- to display a text list of PCs network info.

MS Windows users can get the MAC address by opening a command shell (DOS prompt) and entering net diag /s and you will be asked for the computer Netbios name and enter key--the MAC address displayed next Permanent Node Name

MS Windows users can get the MAC address by opening a command shell (DOS prompt) and entering winipcfg if TCP/IP protocols are already installed.

TCP/IP - Transmission Control Protocol / Internet Protocol creates a connection between sender and receiver using port numbers for a particular device; ie: SMTP Port 25
 

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MTU Maximum Transmission Unit - is the default packet Windows uses to negotiate when a connection is opened between two computers, they must agree on an MTU by comparing MTU and selecting the smaller of the two. If it is set too large for routers, it is then fragmented into packet size and can take double the amount of time it takes to send a single packet.

UART Universal Asynchronous Receiver Transmitter Data flow between the serial port and the modem is governed by a UART chip, which can contain no data buffers, single-byte data buffers or 16-byte data buffers. All data flows between the serial port and the modem via the UART

RWIN (TCP Receive Window) determines how much data the receiving computer is prepared to receive. RWIN value that is set too high will result in greater data loss if the packet is lost or damaged in transit. RWIN value that is set too low will produce poor throughput.

MSS (Maximum Segment Size) is the largest segment of TCP data that Winsock is prepared to receive on a particular connection. When the TCP connection is initially established, both uses the minimum of each other's MSS value.

If the MSS is too low, the data/header ratio will be low. If the MSS is too high, will lead to large IP packets or datagram will tend to fragment in transit where other networks may be having smaller MTU. Hence, performance can be increase by reducing MSS value.

Since packet headers are normally 40 bytes in length, your MSS value should always be set to MTU value minus 40 (i.e. if your MTU is 1500 the set MSS to 1460) at least 40 less than the value of the MTU

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How do I broadcast email through a firewall?
Sending email through a firewall requires the firewall to be setup to allow email messages a free path to travel.