TCP/IP Fundamentals Acronyms - Srickperry

Explanation
The Internet Control Message Protocol (ICMP) enables systems on a TCP/IP network to share status and error information. You can use the status information to detect network trouble. ICMP messages are encapsulated within IP datagrams so that they may be routed throughout a network. Two programs that use ICMP messages are Ping and Tracert.

In general, the term packet applies to any message formatted as a packet, while the term datagram is generally reserved for packets of an "unreliable" service.[1] A "reliable" service is one that notifies the user if delivery fails, while an "unreliable" one does not notify the user if delivery fails.

Explanation
NFS uses an interface that runs on top of TCP/IP networks called the Virtual File System (VFS), which is responsible for making the resource available to a local application. The local application makes the call to the resource as if it were a local resource, and the application never learns that the resource is on a remote system—NFS makes the location and platform of the remote resource transparent to the application and users.

Explanation
The Lightweight Directory Access Protocol (LDAP) is the TCP/IP protocol for directory service access that is supported by all the principal directory services, such as Novell’s eDirectory and Microsoft’s Active Directory. LDAP is a protocol that allows LDAP clients to connect to the network database, or directory, and query the database for information about its objects, such as user accounts and printers. For example, a user on the network could find out the phone number of another user by using the LDAP protocol.

This is an EXAM WATCH tidbit.

Explanation
The Dynamic Host Configuration Protocol (DHCP) is responsible for assigning IP address information automatically to systems on the network. The network administrator configures the DHCP server by configuring a scope (a range of addresses) that the server can assign addresses from. The DHCP service may configure a client with all the TCP/IP settings, including the subnet mask, the default gateway, and the addresses of both the DNS server and the WINS server.

Explanation
The Network Time Protocol (NTP) is used to synchronize the clocks of PCs on a network or the Internet. This is accomplished by configuring a server to be the time server, which then is the server from which all other PCs on the network synchronize their time.

Explanation
The Address Resolution Protocol (ARP) provides IP address–to–physical address resolution on a TCP/IP network.

Exam Watch: ARP is responsible for converting an IP address (layer-3 address) to the physical MAC address (layer-2 address).

Explanation
Windows clients support a feature known as automatic private IP addressing (APIPA), which is a feature that provides that, when a Windows client boots up and cannot contact a DHCP server, it will configure itself automatically with a 169.254.x.y address. If there is something wrong with the DHCP server and all the systems on the network cannot obtain an address from the DHCP server, the clients will all assign themselves an address within the 169.254 address range and then be able to communicate with one another.

APIPA does not assign a default gateway, so you will be unable to access resources on a remote network and the Internet—but you can still communicate with systems on your network. When troubleshooting to find out why a machine cannot communicate on the network, watch for systems that have the 169.254.x.y address range because it means they could not find a DHCP server.

Explanation
The Secure Copy Protocol (SCP) is responsible for copying files from a remote server to the local system over a secure connection, ensuring that data in transit is kept confidential. A number of SCP products use an SSH connection to ensure the security of the secure copy operation.

Explanation
The Boot Protocol, known as BOOTP, is used by diskless workstations. When a diskless workstation boots, it does so using an EEPROM on the network card to allow it to load basic drivers and connect to the network by obtaining an IP address automatically.

A BOOTP server, similar to a DHCP server, assigns the diskless workstation an address for the network to allow it to participate on the network. You will see the term BOOTP a lot when it comes to DHCP and routers; a BOOTP-enabled router will allow the DHCP broadcast to cross the router so that a DHCP server can be found on the other side of the network.

Explanation
The Server Message Block (SMB) protocol, used primarily by Microsoft operating systems, is responsible for sharing files and printers on a system and making those resources available to SMB clients on the network. SMB is an application-layer protocol that runs on top of TCP/IP, IPX, and NetBEUI and relies on those protocols for transport functionality.

SMB is a term that is being phased out. Microsoft is now using the term Common Internet File System (CIFS) instead of SMB. Either way, SMB and CIFS are protocols responsible for allowing access to a remote file system as if it were stored on the local system in a Microsoft environment.

Explanation
The big question is “How does the NAT device know which internal system to send the response to when data is returned from the Internet?” This is an important question because all of the packets will be returned to whatever the public address is on the NAT device. This is where Port Address Translation (PAT) comes in. If you look at Figure 4-17, you will see that the NAT device using port addressing is keeping track of not only the IP address of the system sending outbound traffic, but also the port used by the application on the private system. The source address of the outbound packet is converted from the IP address of the private system to the IP address of the public interface on the NAT device. Also, the port used by the application on the sending computer is then converted to a unique port address used by the NAT device. All IP addresses and port addresses are then stored in the NAT table, known as the port address table, and then the packet is sent to destination system on the Internet.




When a response comes back from the Internet destined for a port on the NAT device, the packet is then translated to use the original private IP address and port number of the original source system. After the header of the packet is replaced with original IP and port information, the NAT device then sends the data to the internal system.

Explanation
The Simple Network Management Protocol (SNMP) is an Internet standard that provides a simple method for remotely managing virtually any network device that supports SNMP. A network device can be a network card in a server; a program or service running on a server; or a network device such as a hub, switch, or router.

The SNMP standard defines a two-tiered approach to network device management: a central management system and the management information base (MIB) located on the managed device. The management system can monitor one or many MIBs, allowing for centralized management of a network. From a management system, you can see valuable performance and network device operation statistics, enabling you to diagnose network health without leaving your office.

Explanation
News clients use the Network News Transfer Protocol (NNTP) to send and retrieve news articles to a newsgroup.

Explanation
The Server Message Block (SMB) protocol, used primarily by Microsoft operating systems, is responsible for sharing files and printers on a system and making those resources available to SMB clients on the network. SMB is an application-layer protocol that runs on top of TCP/IP, IPX, and NetBEUI and relies on those protocols for transport functionality.

SMB is a term that is being phased out. Microsoft is now using the term Common Internet File System (CIFS) instead of SMB. Either way, SMB and CIFS are protocols responsible for allowing access to a remote file system as if it were stored on the local system in a Microsoft environment.

Explanation
The line printer daemon (LPD) is a printer protocol, or service, installed on the print server to allow line printer remote (LPR) clients to send print requests to the print server. When LPD receives the print request, it stores the print request in a queue until the printer becomes available.

Explanation
The IP protocol on the router is responsible for decrementing (usually by a value of 1) the TTL (time to live) of the packet to prevent it from running around in a “network loop.” Windows operating systems have a default TTL of 128.

Explanation
The Internet Message Access Protocol, version 4 (IMAP4) is another protocol similar to POP3 that allows clients to retrieve messages from a mail server. IMAP4 allows additional folders other than the four basic ones provided with POP3. For example, you can use an IMAP4 client to connect to public folders stored on an Exchange Server.

Explanation
The Secure Shell (SSH) is a program used to create a shell, or session, with a remote system. Once the remote session is established, the client can execute commands within this shell and copy files to the local system. SSH has a major purpose in life, and that is to support remote shells with support for secure authentication and encrypted communication.

Explanation
DNS is used as our solution to convert FQDNs to IP addresses.

Explanation
Most users on the network connect to resources by using a friendly name such as www.gleneclarke.com—this style of name, known as a fully qualified domain name (FQDN), must be converted to an IP address before communication can occur.

Explanation
The Windows Internet Naming Service (WINS) provides name resolution for NetBIOS names to matching IP addresses and is popular on large Microsoft networks. WINS is very similar to DNS but contains a database of different-style names—NetBIOS names instead of fully qualified domain names.

NetBIOS names are computer names like \\rickp , \\media , \\compaq ...etc.

Explanation
Another term you will see that deals with NAT is Secure Network Address Translation, or SNAT. Some NAT devices include proxy features as well. These features give you the opportunity to configure different types of clients for the NAT device; for example, you could configure all the clients as proxy clients, or secure NAT clients.

Explanation
If SMB is the file-sharing protocol in Microsoft environments and NFS is the filesharing protocol in UNIX environments, what is responsible for allowing access to files on remote systems in the Macintosh world? You guessed it; the AppleTalk Filing Protocol (AFP) is responsible for allowing Macintosh systems to access remote file systems on an AppleTalk network.

Explanation
The Address Resolution Protocol (ARP) provides IP address–to–physical address resolution on a TCP/IP network.

Exam Watch: ARP is responsible for converting an IP address (layer-3 address) to the physical MAC address (layer-2 address).

Explanation
The Simple Network Management Protocol (SNMP) is an Internet standard that provides a simple method for remotely managing virtually any network device that supports SNMP. A network device can be a network card in a server; a program or service running on a server; or a network device such as a hub, switch, or router.

The SNMP standard defines a two-tiered approach to network device management: a central management system and the management information base (MIB) located on the managed device. The management system can monitor one or many MIBs, allowing for centralized management of a network. From a management system, you can see valuable performance and network device operation statistics, enabling you to diagnose network health without leaving your office.

Explanation
The Internet Message Access Protocol, version 4 (IMAP4) is another protocol similar to POP3 that allows clients to retrieve messages from a mail server. IMAP4 allows additional folders other than the four basic ones provided with POP3. For example, you can use an IMAP4 client to connect to public folders stored on an Exchange Server.

Explanation
The Internet Control Message Protocol (ICMP) enables systems on a TCP/IP network to share status and error information. You can use the status information to detect network trouble. ICMP messages are encapsulated within IP datagrams so that they may be routed throughout a network. Two programs that use ICMP messages are Ping and Tracert.

In general, the term packet applies to any message formatted as a packet, while the term datagram is generally reserved for packets of an "unreliable" service.[1] A "reliable" service is one that notifies the user if delivery fails, while an "unreliable" one does not notify the user if delivery fails.

Explanation
The Internet Control Message Protocol (ICMP) enables systems on a TCP/IP network to share status and error information. You can use the status information to detect network trouble. ICMP messages are encapsulated within IP datagrams so that they may be routed throughout a network. Two programs that use ICMP messages are Ping and Tracert.

In general, the term packet applies to any message formatted as a packet, while the term datagram is generally reserved for packets of an "unreliable" service.[1] A "reliable" service is one that notifies the user if delivery fails, while an "unreliable" one does not notify the user if delivery fails.

Explanation
The Simple Network Management Protocol (SNMP) is an Internet standard that provides a simple method for remotely managing virtually any network device that supports SNMP. A network device can be a network card in a server; a program or service running on a server; or a network device such as a hub, switch, or router.

The SNMP standard defines a two-tiered approach to network device management: a central management system and the management information base (MIB) located on the managed device. The management system can monitor one or many MIBs, allowing for centralized management of a network. From a management system, you can see valuable performance and network device operation statistics, enabling you to diagnose network health without leaving your office.

Explanation
The Simple Network Management Protocol (SNMP) is an Internet standard that provides a simple method for remotely managing virtually any network device that supports SNMP. A network device can be a network card in a server; a program or service running on a server; or a network device such as a hub, switch, or router.

The SNMP standard defines a two-tiered approach to network device management: a central management system and the management information base (MIB) located on the managed device. The management system can monitor one or many MIBs, allowing for centralized management of a network. From a management system, you can see valuable performance and network device operation statistics, enabling you to diagnose network health without leaving your office.

Explanation
The Simple Network Management Protocol (SNMP) is an Internet standard that provides a simple method for remotely managing virtually any network device that supports SNMP. A network device can be a network card in a server; a program or service running on a server; or a network device such as a hub, switch, or router.

The SNMP standard defines a two-tiered approach to network device management: a central management system and the management information base (MIB) located on the managed device. The management system can monitor one or many MIBs, allowing for centralized management of a network. From a management system, you can see valuable performance and network device operation statistics, enabling you to diagnose network health without leaving your office.

Explanation
The Windows Internet Naming Service (WINS) provides name resolution for NetBIOS names to matching IP addresses and is popular on large Microsoft networks. WINS is very similar to DNS but contains a database of different-style names—NetBIOS names instead of fully qualified domain names.

NetBIOS names are computer names like \\rickp , \\media , \\compaq ...etc.

Explanation
The Internet Message Access Protocol, version 4 (IMAP4) is another protocol similar to POP3 that allows clients to retrieve messages from a mail server. IMAP4 allows additional folders other than the four basic ones provided with POP3. For example, you can use an IMAP4 client to connect to public folders stored on an Exchange Server.

Explanation
The Internet Control Message Protocol (ICMP) enables systems on a TCP/IP network to share status and error information. You can use the status information to detect network trouble. ICMP messages are encapsulated within IP datagrams so that they may be routed throughout a network. Two programs that use ICMP messages are Ping and Tracert.

In general, the term packet applies to any message formatted as a packet, while the term datagram is generally reserved for packets of an "unreliable" service.[1] A "reliable" service is one that notifies the user if delivery fails, while an "unreliable" one does not notify the user if delivery fails.

Explanation
The Internet Control Message Protocol (ICMP) enables systems on a TCP/IP network to share status and error information. You can use the status information to detect network trouble. ICMP messages are encapsulated within IP datagrams so that they may be routed throughout a network. Two programs that use ICMP messages are Ping and Tracert.

In general, the term packet applies to any message formatted as a packet, while the term datagram is generally reserved for packets of an "unreliable" service.[1] A "reliable" service is one that notifies the user if delivery fails, while an "unreliable" one does not notify the user if delivery fails.

Explanation
The Dynamic Host Configuration Protocol (DHCP) is responsible for assigning IP address information automatically to systems on the network. The network administrator configures the DHCP server by configuring a scope (a range of addresses) that the server can assign addresses from. The DHCP service may configure a client with all the TCP/IP settings, including the subnet mask, the default gateway, and the addresses of both the DNS server and the WINS server.

Explanation
DNS is used as our solution to convert FQDNs to IP addresses.

Explanation
The Internet Control Message Protocol (ICMP) enables systems on a TCP/IP network to share status and error information. You can use the status information to detect network trouble. ICMP messages are encapsulated within IP datagrams so that they may be routed throughout a network. Two programs that use ICMP messages are Ping and Tracert.

In general, the term packet applies to any message formatted as a packet, while the term datagram is generally reserved for packets of an "unreliable" service.[1] A "reliable" service is one that notifies the user if delivery fails, while an "unreliable" one does not notify the user if delivery fails.

Explanation
The Simple Network Management Protocol (SNMP) is an Internet standard that provides a simple method for remotely managing virtually any network device that supports SNMP. A network device can be a network card in a server; a program or service running on a server; or a network device such as a hub, switch, or router.

The SNMP standard defines a two-tiered approach to network device management: a central management system and the management information base (MIB) located on the managed device. The management system can monitor one or many MIBs, allowing for centralized management of a network. From a management system, you can see valuable performance and network device operation statistics, enabling you to diagnose network health without leaving your office.