This page has been setup to secure my systems.
Feel free to use this tools. Use them only to audit your own system(s) as system owners do not like to be audited by other individuals.

This page includes explainations as well.
Click here if you are only interested in the link summary.

Last update of this page has been September 29th 2002.
In case of broken links, additional links or any other comments, do not hesitate to sent a mail to berne.houwer@planet.nl

Ping is a basic Internet program that lets you verify that a particular IP address exists and can accept requests. The verb ping means the act of using the ping utility or command. Ping is used diagnostically to ensure that a host computer you are trying to reach is actually operating. If, for example, a user can't ping a host, then the user will be unable to use the File Transfer Protocol (FTP) to send files to that host. Ping can also be used with a host that is operating to see how long it takes to get a response back.

Source: whatis.techtarget.com

Traceroute is a utility that records the route (the specific gateway computers at each hop) through the Internet between your computer and a specified destination computer. It also calculates and displays the amount of time each hop took. Traceroute is a handy tool both for understanding where problems are in the Internet network and for getting a detailed sense of the Internet itself. Another utility, PING, is often used prior to using traceroute to see whether a host is present on the network.

Source: whatis.techtarget.com

Via these Looking glasses you can gather information from and about routers like ping, traceroute, routing information regarding several routing protocols, interface information and other information.

Via Telnet sessions to these Route servers a very wide range of operational status information can be showed!

The domain name system (DNS) is the way that Internet domain name are located and translated into Internet Protocol addresses. A domain name is a meaningful and easy-to-remember "handle" for an Internet address.
Because maintaining a central list of domain name/IP address correspondences would be impractical, the lists of domain names and IP addresses are distributed throughout the Internet in a hierarchy of authority. There is probably a DNS server within close geographic proximity to your access provider that maps the domain names in your Internet requests or forwards them to other servers in the Internet.

Forward DNS lookup is using an Internet domain name to find an IP address. Reverse DNS lookup is using an Internet IP address to find a domain name. When you enter the address for a Web site at your browser (the address is formally called the Uniform Resource Locator, or Uniform Resource Locator), the address is transmitted to a nearby router which does a forward DNS lookup in a routing table to locate the IP address. Forward domain name system (which stands for Domain Name System) lookup is the more common lookup since most users think in terms of domain names rather than IP addresses. However, occasionally you may see a Web page with a URL in which the domain name part is expressed as an IP address (sometimes called a dot address) and want to be able to see its domain name. nslookup is an Internet facility that lets you do either forward or reverse DNS lookup yourself. It comes with some operating systems or you can download the program and install it in your computer.

Source: whatis.techtarget.com

Finger is a program that tells you the name associated with an e-mail address. It may also tell you whether they are currently logon at their system or their most recent logon session and possibly other information, depending on the data that is maintained about users on that computer. Finger originated as part of BSD UNIX.

Source: whatis.techtarget.com

Whois is a program that will tell you the owner of any second-level domain name who has registered it with Network Solutions, formerly the only and still the most widely used of the Internet registrars of the com, net, and org domain names. If a Web site obtained its domain name from Network Solutions, you can look up the name of the owner of the Web site by entering (for example): aol.com and whois will tell you the owner of that second-level domain name. Whois can also be used to find out whether a domain name is available or has already been taken. If you enter a domain name you are considering and the search result is "No match," the domain name is likely to be available and you can apply to register it.

Source: whatis.techtarget.com

The CORE Network Management Database contains information about IP address space allocations and assignments, routing policies and reverse delegations regarding .com, .org and .net domains.

The RIPE Network Management Database contains information about IP address space allocations and assignments, routing policies and reverse delegations in the RIPE (European) region.

The ARIN Network Management Database contains information about IP address space allocations and assignments, routing policies and reverse delegations in the ARIN (American) region.

The APNIC Network Management Database contains information about IP address space allocations and assignments, routing policies and reverse delegations in the APNIC (Asia-Pacific) region.

The NIC is operated by the Defense Information Systems Agency (DISA). It provides information and services that are mission critical to the operation of the worldwide IP router Defense Information Systems Network and other DoD sponsored networks.

Converting host names to location comes in handy when you want to plot your WWW accesses on the globe.

"Smurf" is the name of an automated program that attacks a network by exploiting Internet Protocol (Internet Protocol) broadcast addressing and certain other aspects of Internet operation. Smurf and similar programs can cause the attacked part of a network to become "inoperable." The exploit of smurfing, as it has come to be known, takes advantage of certain known characteristics of the Internet Protocol (IP) and the Internet Control Message Protocol (Internet Control Message Protocol). The ICMP is used by network nodes and their administrators to exchange information about the state of the network. ICMP can be used to Packet Internet or Inter-Network Groper other nodes to see if they are operational. An operational node returns an echo message in response to a ping message.

Source: whatis.techtarget.com

A port scan is a series of messages sent by someone attempting to break into a computer to learn which computer network services, each associated with a "well-known" port number, the computer provides. Port scanning, a favorite approach of computer cracker, gives the assailant an idea where to probe for weaknesses. Essentially, a port scan consists of sending a message to each port, one at a time. The kind of response received indicates whether the port is used and can therefore be probed for weakness.

Source: whatis.techtarget.com

The Hypertext Transfer Protocol (HTTP) is the set of rules for exchanging files (text, graphic images, sound, video, and other multimedia files) on the World Wide Web. Relative to the TCP/IP suite of protocols (which are the basis for information exchange on the Internet), HTTP is an application protocol.
Essential concepts that are part of HTTP include (as its name implies) the idea that files can contain references to other files whose selection will elicit additional transfer requests. Any Web server machine contains, in addition to the HTML and other files it can serve, an HTTP daemon, a program that is designed to wait for HTTP requests and handle them when they arrive. Your Web browser is an HTTP client, sending requests to server machines. When the browser user enters file requests by either "opening" a Web file (typing in a Uniform Resource Locator) or clicking on a hypertext link, the browser builds an HTTP request and sends it to the Internet Protocol address indicated by the URL. The HTTP daemon in the destination server machine receives the request and, after any necessary processing, the requested file is returned.

Source: whatis.techtarget.com

Since replaced by the Transport Layer Security (TLS) standard, the Secure Sockets Layer (SSL) remains a commonly-used protocol for managing the security of a message transmission on the Internet. TLS is based on SSL. SSL uses a program layer located between the Internet's Hypertext Transfer Protocol (HTTP) and Transport Control Protocol (TCP) layers. SSL is included as part of both the Microsoft and Netscape browsers and most Web server products. Developed by Netscape, SSL also gained the support of Microsoft and other Internet client/server developers as well and became the de facto standard until evolving into Transport Layer Security. The "sockets" part of the term refers to the sockets method of passing data back and forth between a client and a server program in a network or between program layers in the same computer. SSL uses the public-and-private key encryption system from RSA, which also includes the use of a digital certificate.
TLS and SSL are an integral part of most Web browsers (clients) and Web servers. If a Web site is on a server that supports SSL, SSL can be enabled and specific Web pages can be identified as requiring SSL access. Any Web server can be enabled by using Netscape's SSLRef program library which can be downloaded for noncommercial use or licensed for commercial use.
TLS and SSL are not interoperable. However, a message sent with TLS can be handled by a client that handles SSL but not TLS.

Source: whatis.techtarget.com

Simple Network Management Protocol (SNMP) is the protocol governing network management and the monitoring of network devices and their functions. It is not necessarily limited to TCP/IP networks.

Source: whatis.techtarget.com

You can get this systems to test your mailserver to see if it's open for 3th party mail relaying.

This HTTP to TELNET gateway allows you to access any telnet connection from the WWW without the need for any special client software, except (currently) the support of frames. The data from the server to your client will go at the same speed as a normal telnet connection (but is of course slowed down by the connection of this server), but your commands will be sent in line-mode and using the HTTP protocol, and will therefore be slower. Fill in the address and port you wish to connect to to make a telnet connection. Note that all data you enter in this session will not be private and can be observed by the administrator of this server. This includes but is not limited to the login and password combinations.

Telnet is the way you can access someone else's computer, assuming they have given you permission. (Such a computer is frequently called a host computer.) More technically, Telnet is a user command and an underlying TCP/IP protocol for accessing remote computers. On the Web, HTTP and FTP protocols allow you to request specific files from remote computers, but not to actually be logged on as a user of that computer. With Telnet, you log on as a regular user with whatever privileges you may have been granted to the specific application and data on that computer.
A Telnet command request looks like this (the computer name is made-up): telnet the.libraryat.whatis.edu
The result of this request would be an invitation to log on with a userid and a prompt for a password. If accepted, you would be logged on like any user who used this computer every day.
Telnet is most likely to be used by program developers and anyone who has a need to use specific applications or data located at a particular host computer.

Source: whatis.techtarget.com

File Transfer Protocol (FTP), a standard Internet , is the simplest way to exchange files between computers on the Internet. Like the Hypertext Transfer Protocol (HTTP), which transfers displayable Web pages and related files, and the Simple Mail Transfer Protocol (SMTP), which transfers e-mail, FTP is an application protocol that uses the Internet's TCP/IP protocols. FTP is commonly used to transfer Web page files from their creator to the computer that acts as their server for everyone on the Internet. It's also commonly used to download programs and other files to your computer from other servers.

Source: whatis.techtarget.com

A remailer is an Internet site to which you can send e-mail for forwarding to an intended destination while concealing your own e-mail address. E-mail sent through a remailer is sometimes known as anonymous e-mail. There may be valid reasons for wanting to conceal your e-mail address (and personal identity) from an e-mail recipient. There are, of course, unworthy reasons, too. However, advocates of anonymous e-mail and remailer services remind us that having the right to conceal your identity in a note can, on occasion, be socially useful and the practice should be possible.

Source: whatis.techtarget.com

Usenet is a collection of user-submitted notes or messages on various subjects that are posted to servers on a worldwide network. Each subject collection of posted notes is known as a newsgroup. There are thousands of newsgroups and it is possible for you to form a new one. Most newsgroups are hosted on Internet-connected servers, but they can also be hosted from servers that are not part of the Internet. Usenet's original protocol was UNIX-to-UNIX Copy (UUCP), but today the Network News Transfer Protocol (NNTP) is used.

Source: whatis.techtarget.com

Privacy Analysis of your Internet Connection.
Some Information that is collected about you when visiting a web site...

A technical definition of the World Wide Web is: all the resources and users on the Internet that are using the Hypertext Transfer Protocol (HTTP).
A broader definition comes from the organization that Web inventor Tim Berners-Lee helped found, the World Wide Web Consortium (W3C ):
"The World Wide Web is the universe of network-accessible information, an embodiment of human knowledge."

Source: whatis.techtarget.com

A subnet (short for "subnetwork") is an identifiably separate part of an organization's network. Typically, a subnet may represent all the machines at one geographic location, in one building, or on the same local area network (LAN). Having an organization's network divided into subnets allows it to be connected to the Internet with a single shared network address. Without subnets, an organization could get multiple connections to the Internet, one for each of its physically separate subnetworks, but this would require an unnecessary use of the limited number of network numbers the Internet has to assign. It would also require that Internet routing tables on gateways outside the organization would need to know about and have to manage routing that could and should be handled within an organization.
The Internet is a collection of networks whose users communicate with each other. Each communication carries the address of the source and destination networks and the particular machine within the network associated with the user or host computer at each end. This address is called the IP address (Internet Protocol address). This 32-bit IP address has two parts: one part identifies the network (with the network number) and the other part identifies the specific machine or host within the network (with the host number). An organization can use some of the bits in the machine or host part of the address to identify a specific subnet. Effectively, the IP address then contains three parts: the network number, the subnet number, and the machine number.

Source: whatis.techtarget.com

At PC Pitstop they can help you get your PC in top form -- running fast, stable and secure. PC Pitstop runs diagnostics on your PC to identify things that might help improve performance. The process is fully automated, private and safe. After the diagnostics run, they'll give you tips for improving all kinds of things. Best of all, the service is free!

Decryption is the process of converting encrypted data back into its original form, so it can be understood.

This is the Internet's original and most complete index of online phone books, with over 400 links to Yellow Pages, White Pages, Business Directories, Email Addresses and Fax Listings from over 170 countries all around the world.

This site gives a very complete overview of telecommunication providers worldwide.

The primary purpose of this list of lists of Internet access providers is to help people locate appropriate Internet access providers, but it is been hoped that making available information about Internet access options will encourage competition and encourage Internet access providers to improve.

The Internet Traffic Report monitors the flow of data around the world. It then displays a value between zero and 100. Higher values indicate faster and more reliable connections.

This sites are giving a real time world wide virus overview.

A virus is a piece of programming code usually disguised as something else that causes some unexpected and, for the victim, usually undesirable event and which is often designed so that it is automatically spread to other computer users. Viruses can be transmitted by sending them as attachments to an e-mail note, by downloading infected programming from other sites, or be present on a diskette or CD. The source of the e-mail note, downloaded file, or diskette you've received is often unaware of the virus. Some viruses wreak their effect as soon as their code is executed; other viruses lie dormant until circumstances cause their code to be executed by the computer. Some viruses are playful in intent and effect ("Happy Birthday, Ludwig!") and some can be quite harmful, erasing data or causing your hard disk to require reformatting.
Generally, there are three main classes of viruses:

• File infectors. Some file infector viruses attach themselves to program files, usually selected .COM or .EXE files. Some can infect any program for which execution is requested, including .SYS, .OVL, .PRG, and .MNU files. When the program is loaded, the virus is loaded as well. Other file infector viruses arrive as wholly-contained programs or scripts sent as an attachment to an e-mail note.
• System or boot-record infectors. These viruses infect executable code found in certain system areas on a disk. They attach to the DOS boot sector on diskettes or the Master Boot Record on hard disks. A typical scenario (familiar to the author) is to receive a diskette from an innocent source that contains a boot disk virus. When your operating system is running, files on the diskette can be read without triggering the boot disk virus. However, if you leave the diskette in the drive, and then turn the computer off or reload the operating system, the computer will look first in your A drive, find the diskette with its boot disk virus, load it, and make it temporarily impossible to use your hard disk. (Allow several days for recovery.) This is why you should make sure you have a bootable floppy.
• Macro viruses. These are among the most common viruses, and they tend to do the least damage. Macro viruses infect your Microsoft Word application and typically insert unwanted words or phrases.

The best protection against a virus is to know the origin of each program or file you load into your computer or open from your e-mail program. Since this is difficult, you can buy anti-virus software that can screen e-mail attachments and also check all of your files periodically and remove any viruses that are found. From time to time, you may get an e-mail message warning of a new virus. Unless the warning is from a source you recognize, chances are good that the warning is a virus hoax.

Source: whatis.techtarget.com

A firewall is a set of related programs, located at a network gateway server, that protects the resources of a private network from users from other networks. (The term also implies the security policy that is used with the programs.) An enterprise with an intranet that allows its workers access to the wider Internet installs a firewall to prevent outsiders from accessing its own private data resources and for controlling what outside resources its own users have access to.
Basically, a firewall, working closely with a router program, examines each network packet to determine whether to forward it toward its destination. A firewall also includes or works with a proxy server that makes network requests on behalf of workstation users. A firewall is often installed in a specially designated computer separate from the rest of the network so that no incoming request can get directly at private network resources.
There are a number of firewall screening methods. A simple one is to screen requests to make sure they come from acceptable (previously identified) domain name and Internet Protocol addresses. For mobile users, firewalls allow remote access in to the private network by the use of secure logon procedures and authentication certificates.
A number of companies make firewall products. Features include logging and reporting, automatic alarms at given thresholds of attack, and a graphical user interface for controlling the firewall.

Source: whatis.techtarget.com

Intrusion detection (ID) is a type of security management system for computers and networks. An ID system gathers and analyzes information from various areas within a computer or a network to identify possible security breaches, which include both intrusions (attacks from outside the organization) and misuse (attacks from within the organization). ID uses vulnerability assessment (sometimes refered to as scanning), which is a technology developed to assess the security of a computer system or network.
Intrusion detection functions include:
• Monitoring and analyzing both user and system activities
• Analyzing system configurations and vulnerabilities
• Assessing system and file integrity
• Ability to recognize patterns typical of attacks
• Analysis of abnormal activity patterns
• Tracking user policy violations

ID systems are being developed in response to the increasing number of attacks on major sites and networks, including those of the Pentagon, the White House, NATO, and the U.S. Defense Department. The safeguarding of security is becoming increasingly difficult, because the possible technologies of attack are becoming ever more sophisticated; at the same time, less technical ability is required for the novice attacker, because proven past methods are easily accessed through the Web.
Typically, an ID system follows a two-step process. The first procedures are host-based and are considered the passive component, these include: inspection of the system's configuration files to detect inadvisable settings; inspection of the password files to detect inadvisable passwords; and inspection of other system areas to detect policy violations. The second procedures are network-based and are considered the active component: mechanisms are set in place to reenact known methods of attack and to record system responses.
In 1998, ICSA.net, a leading security assurance organization, formed the Intrusion Detection Systems Consortium (IDSC) as an open forum for ID product developers with the aim of disseminating information to the end user and developing industry standards.

Source: whatis.techtarget.com

Most browsers, such as those from Netscape and Microsoft, provide Usenet support and access to any newsgroups that you select. On the Web, Google and other sites provide a subject-oriented drectory as well as a search approach to newsgroups and help you register to participate in them. In addition, there are other newsgroup readers, such as Knews, that run as separate programs.

Source: whatis.techtarget.com

Whatis is a knowledge exploration tool about information technology, especially about the Internet and computers. It contains over 2,000 individual encyclopedic definition/topics and a number of quick-reference pages. The topics contain about 12,000 hyperlinked cross-references between definition-topics and to other sites for further information. They try hard to keep it up-to-date.

Source: whatis.techtarget.com

A Request for Comments (RFC) is a formal document from the Internet Engineering Task Force (IETF) that is the result of committee drafting and subsequent review by interested parties. Some RFCs are informational in nature. Of those that are intended to become Internet standards, the final version of the RFC becomes the standard and no further comments or changes are permitted. Change can occur, however, through subsequent RFCs that supercede or elaborate on all or parts of previous RFCs.

Source: whatis.techtarget.com

Susceptibility to attack or harm.

Source: www.cio.usmc.mil

IP Protocol Suite describes:

Network layer protocols:

These protocols are assigned an Ethertype number.

• ARP, Address Resolution Protocol.
• DRARP, Dynamic RARP.
• InARP, Inverse Address Resolution Protocol.
• IP, Internet Protocol.
• IPv6, Internet Protocol version 6.
• RARP, Reverse Address Resolution Protocol.
• TP/IX.

Transport layer protocols:

These protocols are assigned an IP Protocol number.

• AH, IP Authentication Header.
• AX.25.
• CBT, Core Based Trees.
• EGP, Exterior Gateway Protocol.
• ESP, Encapsulating Security Payload.
• GGP, Gateway to Gateway Protocol.
• GRE, Generic Routing Encapsulation.
• HMP, Host Monitoring Protocol.
• ICMP, Internet Control Message Protocol.
• ICMPv6, Internet Control Message Protocol for IPv6.
• IDPR, Inter-Domain Policy Routing Protocol.
• IFMP, Ipsilon Flow Management Protocol.
• IGMP, Internet Group Management Protocol.
• IP in IP Encapsulation.
• IPPCP, IP Payload Compression Protocol.
• IRTP, Internet Reliable Transaction Protocol.
• Minimal Encapsulation Protocol.
• MOSPF, Multicast Open Shortest Path First.
• MTP, Multicast Transport Protocol.
• NARP, NBMA Address Resolution Protocol.
• NETBLT, Network Block Transfer.
• NVP, Network Voice Protocol.
• OSPF, Open Shortest Path First Routing Protocol.
• PGM, Pragmatic General Multicast.
• PIM, Protocol Independent Multicast.
• PTP, Performance Transparency Protocol.
• RDP, Reliable Data Protocol.
• RSVP, Resource ReSerVation Protocol.
• SCTP, Stream Control Transmission Protocol.
• SDRP, Source Demand Routing Protocol.
• SKIP, Simple Key management for Internet Protocol.
• ST, Internet Stream Protocol.
• TCP, Transmission Control Protocol.
• TMux, Transport Multiplexing Protocol.
• UDP, User Datagram Protocol.
• VMTP, Versatile Message Transaction Protocol.
• VRRP, Virtual Router Redundancy Protocol.

Application layer protocols:

These protocols are assigned one or more UDP or TCP port numbers.

• ACAP, Application Configuration Access Protocol.
• AgentX.
• ATMP, Ascend Tunnel Management Protocol.
• AURP, AppleTalk Update-based Routing Protocol.
• Authentication Server Protocol.
• BFTP, Background File Transfer Program.
• BGP, Border Gateway Protocol.
• BOOTP, Bootstrap Protocol.
• CFDP, Coherent File Distribution Protocol.
• Chargen, Character Generator Protocol.
• CLDAP, Connection-less Lightweight X.500 Directory Access Protocol.
• COPS, Common Open Policy Service.
• Daytime, Daytime Protocol.
• DCAP, Data Link Switching Client Access Protocol.
• DHCP, Dynamic Host Configuration Protocol.
• DICT, Dictionary Server Protocol.
• Discard, Discard Protocol.
• DIXIE.
• DNS, Domain Name System.
• DRAP, Data Link Switching Remote Access Protocol.
• DTCP, Dynamic Tunnel Configuration Protocol.
• Echo.
• EMSD, Efficient Mail Submission and Delivery.
• ESRO, Efficient Short Remote Operations.
• ETFTP, Enhanced Trivial File Transfer Protocol.
• Finger.
• FTP, File Transfer Protocol.
• Gopher.
• HOSTNAME.
• HSRP, Hot Standby Router Protocol.
• HTTP, HyperText Transfer Protocol.
• ICP, Internet Cache Protocol.
• IKE, Internet Key Exchange.
• IMAP, Interactive Mail Access Protocol.
• IPP, Internet Printing Protocol.
• IRC, Internet Relay Chat.
• ISAKMP, Internet Security Association and Key Management Protocol.
• Kerberos.
• Kermit.
• L2F, Layer 2 Forwarding.
• L2TP, Level 2 Tunneling Protocol.
• LDAP, Lightweight Directory Access Protocol.
• LDP, Label Distribution Protocol.
• LDP, Loader Debugger Protocol.
• LMTP, Local Mail Transfer Protocol.
• LPR.
• MADCAP, Multicast Address Dynamic Client Allocation Protocol.
• MASC, Multicast Address-Set Claim.
• MATIP, Mapping of Airline Traffic over Internet Protocol.
• MGCP, Multimedia Gateway Control Protocol.
• MPP, Message Posting Protocol.
• MTP, Mail Transfer Protocol.
• NAS, Netnews Administration System.
• NFILE.
• NFS, Network File System.
• NNTP, Network News Transfer Protocol.
• NTP, Network Time Protocol.
• ODETTE-FTP, ODETTE File Transfer Protocol.
• Ph.
• Photuris.
• POP, Post Office Protocol.
• PPTP, Point to Point Tunneling Protocol.
• PWDGEN, Password Generator Protocol.
• Quote, Quote of the Day Protocol.
• RADIUS, Remote Authentication Dial-In User Service.
• RAP, Internet Route Access Protocol.
• RIP, Routing Information Protocol.
• RIPng.
• Rlogin.
• RLP, Resource Location Protocol.
• RMCP, Remote Mail Checking Protocol.
• RSIP, Realm Specific IP.
• RTCP, RTP Control Protocol.
• RTP, Real-Time Protocol.
• RTSP, Real Time Streaming Protocol.
• RWhois, Referral Whois Protocol.
• Send, Message Send Protocol.
• SFTP, Simple File Transfer Protocol.
• SGMP, Simple Gateway Monitoring Protocol.
• SIFT/UFT, Sender-Initiated/Unsolicited File Transfer.
• SIP, Session Initiation Protocol.
• SLP, Service Location Protocol.
• SMTP, Simple Mail Transfer Protocol.
• SMUX.
• SNMP, Simple Network Management Protocol.
• SNPP, Simple Network Paging Protocol.
• SNTP, Simple Network Time Protocol.
• SOCKS.
• SSP, Switch-to-Switch Protocol.
• STATSRV, Statistics Server.
• Syslog.
• SYSTAT.
• TACACS.
• Telnet.
• TFTP, Trivial File Transfer Protocol.
• Time, Time Protocol.
• TRIP, Telephone Routing over IP.
• TSP, Time Stamp Protocol.
• UMSP, Unified Memory Space Protocol.
• UUCP.
• VEMMI, VErsatile MultiMedia Interface.
• Whois.
• Whois++.
• Z39.50.

Well known TCP/UDP ports.

Source: www.networksorcery.com

• On computer and telecommunication devices, a port (noun) is generally a specific place for being physically connected to some other device, usually with a socket and plug of some kind. Typically, a personal computer is provided with one or more serial ports and usually one parallel port. The serial port supports sequential, one bit-at-a-time transmission to peripheral devices such as scanners and the parallel port supports multiple-bit-at-a-time transmission to devices such as printers.
• In programming, a port (noun) is a "logical connection place" and specifically, using the Internet's protocol, TCP/IP, the way a client program specifies a particular server program on a computer in a network. Higher-level applications that use TCP/IP such as the Web protocol, Hypertext Transfer Protocol, have ports with preassigned numbers. These are known as "well-known ports" that have been assigned by the Internet Assigned Numbers Authority (IANA). Other application processes are given port numbers dynamically for each connection. When a service (server program) initially is started, it is said to bind to its designated port number. As any client program wants to use that server, it also must request to bind to the designated port number.
Port numbers are from 0 to 65536. Ports 0 to 1024 are reserved for use by certain privileged services. For the HTTP service, port 80 is defined as a default and it does not have to be specified in the Uniform Resource Locator (URL).
• In programming, to port (verb) is to move an application program from an operating system environment in which it was developed to another operating system environment so it can be run there. Porting implies some work, but not nearly as much as redeveloping the program in the new environment. open standard programming interface (such as those specified in X/Open's 1170 C language specification and Sun Microsystem's Java programming language) minimize or eliminate the work required to port a program.

Source: whatis.techtarget.com

ICMP (Internet Control Message Protocol) is a message control and error-reporting protocol between a host server and a gateway to the Internet. ICMP uses Internet Protocol (IP) datagrams, but the messages are processed by the IP software and are not directly apparent to the application user.

Source: whatis.techtarget.com