Note: My Web pages are best viewed with style sheets enabled.
In my other Web pages, I use terms such as server and domain, which I need to define. Here are simplified definitions that might not be as complete or technically precise as an experienced computer professional might desire.
To simplify browsing, this page might appear in a window or tab separate from the pages where the terms are used. You can leave this page open and return to the page that sent you here without having to reload either. However, after this page has opened on one definition, the user who then selects another term will have to select this page to bring it in front.
Usually, a botnet results from infections by computer viruses or similar malware. The best way to avoid being infected by a botnet is to use effective anti-virus software that is updated regularly.
When a client requests a domain by name, the client's Internet connection accesses the nearest DNS to search its DNS table. If the domain name does not appear in that table, the DNS in turn accesses a farther DNS. This continues until either the name is found or the chain of DNSs is exhausted. Obviously, most DNSs contain www.yahoo.com in their tables. Less well-known domains are carried in only a few tables. All domains are carried in the tables at the root DNSs at the ends of the chains.
Headers are generated when a message is sent. Then more headers are added as the message travels through the Internet. A mail server will generally add even more headers when an E-mail message is received. Often, headers in spam messages are faked to prevent tracing their origins.
Technically, a header as described above is a header field. A group of header fields is the header section of a message. Samples of E-mail, newsgroup, and Web headers are presented in a text page to preserve their actual layout.
The classic IP address (IPv4) is in the form of four groups of 3-digit decimal numbers in the range 0-255 separated by periods; leading zeros in each group are omitted. The IPv4 scheme can result in 4,294,967,296 unique addresses. Many domains have multiple IP addresses to allow multiple connections at the same time. The IPv4 addresses for www.iswest.com range from 188.8.131.52 to 184.108.40.206.
Six-part IP addresses (IPv6) are gradually being introduced because of concerns that not enough distinct four-part IPv4 addresses can exist. With every smart cell-phone, WiFi hot spot, GPS device, and router having its own IP address and with many servers having multiple IP addresses, that concern is very real.
An IPv6 address is in the form of eight groups of 4-digit hexadecimal digits in the range 0-FFFF (0-65535) separated by colons. Leading zeros in each group are omitted. One set of consecutive groups that are all zeros may be replaced by a double colon (::). The number of unique IPv6 addresses is greater than 34 followed by 37 zeros. The IPv6 address for www.big-8.org is represented as 2a01:4f8:120:9382::145, which is actually 2a01:04f8:0120:9382:0000:0000:0000:0145.
When I used a dial-up modem for connecting to the Internet, I got a new IP address each time I connected. This is a dynamic IP address. Before I retired, I had a dedicated ethernet connection at work, which gave me a static, unchanging IP address. Often, DSL and cable modem connections are static; but some ISPs assign a new IP address each time a computer with such a connection reboots or when the modem reboots.
If a domain moves from one host to another, a new IP address is assigned to the domain because IP addresses are associated with a particular host's connection to the Internet. Thus, the old IP address becomes available for reassignment to another domain on the old host.
In addition to domains, other connections to the Internet have IP addresses, including your own computer, which has the IP address
Note: If you connect to the Internet through a local router and then through a modem, that might be the IP address of either of those devices.
There are also dial-up pseudo-POPs, which are very similar to call-forwarding (and might even use that capability). If you dial a pseudo-POP, you actually connect to a different phone number. Thus, when I worked in Los Angeles County, I could call my ISP on a local phone number. I would then connect to a POP in Ventura County more than 40 miles away. If I were to dial the actual POP, it would not be a local call.
Some ISPs do not use this protocol, requiring subscribers to use only the ISP's own proprietary E-mail clients. (See also IMAP.)
Servers generally operate in one of two modes:
Because many hosts host only one server, the term server is often used for the hardware; this can only cause confusion when the same platform is a host to multiple copies of a server or several different servers and might even host some clients. (Good system design, however, generally avoids having clients and servers hosted on the same platform.) Also, a given server might be launched on serveral different hosts when requested; this improves the responsiveness of the server.
A site certificate is digitally signed by a certificate authority (CA). A CA has a root certificate that is used to encrypt part of a site certificate, thereby signing the latter. Actually, there is usually an intermediate certificate that was signed by a root certificate; the intermediate certificate then signed the site certificate.
For all this to work, the site certificate is installed on the Web server along with any intermediate certificates; and the root certificate is installed in a database contained within the user's Web browser. (A frequent problem arises when those who maintain the Web server fail to install the necessary intermediate certificates.) Most browsers come with a large repertoire of root certificates. Also, for this to work, the Web pages are addressed beginning with https instead of http, the s indicating secure. The URI beginning with https must have the domain that agrees with the domain in the site certificate.
At the time this page was last updated, my browser was SeaMonkey 2.26, which had the UA string
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:29.0) Gecko/20100101 SeaMonkey/2.26
(Note that the default UA string for this version of SeaMonkey is Mozilla/5.0 (Windows NT 6.1; WOW64; rv:29.0) Gecko/20100101 Firefox/29.0 SeaMonkey/2.26 where the insertion of Firefox/29.0 is a built-in spoof of Firefox. I have disabled that spoof.)
Your UA string is
NOTE: Accessing a Web page from a server while using a UA that leaves a blank or null UA string is contrary to RFC 1945 and might be considered abusive.
The symbolic address of a Web page or other Internet entity. The URI for this page is http://www.rossde.com/internet/intr_gloss.shtml.
While the term URI (uniform resource identifier) has replaced URL, URL remains in common usage. Although the definition of URI is more generalized than URL, the difference is mostly in technical details.
There is a convention that URIs in text should be bracketed, with a preference for using < and >. If a URI will appear split between two or more lines, this can be especially useful in determining the full extent of the URI. Thus, this page is at <http://www.rossde.com/internet/intr_gloss.shtml>; and my home page is at <http://www.rossde.com/index.html>. However, when entering a URI in a form on a Web page or within an HTML-formatted E-mail message, [ and ] might be a better choice for brackets since < and > have special meanings in HTML.
The WhoIs data for the domain www.wikipedia.org is
Domain ID:D51687756-LROR Domain Name:WIKIPEDIA.ORG Created On:13-Jan-2001 00:12:14 UTC Last Updated On:09-May-2012 00:25:29 UTC Expiration Date:13-Jan-2016 00:12:14 UTC Sponsoring Registrar:MarkMonitor Inc. (R37-LROR) Status:CLIENT DELETE PROHIBITED Status:CLIENT TRANSFER PROHIBITED Status:CLIENT UPDATE PROHIBITED Registrant ID:mmr-116560 Registrant Name:Domain Admin Registrant Organization:Wikimedia Foundation, Inc. Registrant Street1:149 New Montgomery Street Registrant Street2:Third Floor Registrant Street3: Registrant City:San Francisco Registrant State/Province:CA Registrant Postal Code:94105 Registrant Country:US Registrant Phone:+1.4158396885 Registrant Phone Ext.: Registrant FAX:+1.4158820495 Registrant FAX Ext.: Registrant Email:email@example.com Admin ID:mmr-116560 Admin Name:Domain Admin Admin Organization:Wikimedia Foundation, Inc. Admin Street1:149 New Montgomery Street Admin Street2:Third Floor Admin Street3: Admin City:San Francisco Admin State/Province:CA Admin Postal Code:94105 Admin Country:US Admin Phone:+1.4158396885 Admin Phone Ext.: Admin FAX:+1.4158820495 Admin FAX Ext.: Admin Email:firstname.lastname@example.org Tech ID:mmr-116560 Tech Name:Domain Admin Tech Organization:Wikimedia Foundation, Inc. Tech Street1:149 New Montgomery Street Tech Street2:Third Floor Tech Street3: Tech City:San Francisco Tech State/Province:CA Tech Postal Code:94105 Tech Country:US Tech Phone:+1.4158396885 Tech Phone Ext.: Tech FAX:+1.4158820495 Tech FAX Ext.: Tech Email:email@example.com Name Server:NS0.WIKIMEDIA.ORG Name Server:NS1.WIKIMEDIA.ORG Name Server:NS2.WIKIMEDIA.ORG Name Server: Name Server: Name Server: Name Server: Name Server: Name Server: Name Server: Name Server: Name Server: Name Server: DNSSEC:Unsigned
The WhoIs data for the IPv4 address 220.127.116.11 is
NetRange: 18.104.22.168 - 22.214.171.124 CIDR: 126.96.36.199/17 OriginAS: NetName: ISWEST-BLK-1 NetHandle: NET-207-178-128-0-1 Parent: NET-207-0-0-0-0 NetType: Direct Allocation Comment: ADDRESSES WITHIN THIS BLOCK ARE NON-PORTABLE RegDate: 1996-08-17 Updated: 1998-06-16 Ref: http://whois.arin.net/rest/net/NET-207-178-128-0-1 OrgName: Internet Specialties West OrgId: ISWT Address: 30077 Agoura Court, First Floor City: Agoura Hills StateProv: CA PostalCode: 91301 Country: US RegDate: 1996-08-17 Updated: 2011-09-24 Comment: www.iswest.com Ref: http://whois.arin.net/rest/org/ISWT OrgTechHandle: NOC3563-ARIN OrgTechName: Network Operations Center OrgTechPhone: +1-818-735-3000 OrgTechEmail: firstname.lastname@example.org OrgTechRef: http://whois.arin.net/rest/poc/NOC3563-ARIN OrgAbuseHandle: NOC3563-ARIN OrgAbuseName: Network Operations Center OrgAbusePhone: +1-818-735-3000 OrgAbuseEmail: email@example.com OrgAbuseRef: http://whois.arin.net/rest/poc/NOC3563-ARIN RTechHandle: ISWEST-ADM-ARIN RTechName: Internet Specialties West RTechPhone: +1-818-735-3000 RTechEmail: firstname.lastname@example.org RTechRef: http://whois.arin.net/rest/poc/ISWEST-ADM-ARIN
No, do not ask me to explain each line in these WhoIs results.
Last updated 1 June 2014
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