User manual

RLXIC-SG ♦ Intelligent Cellular IP Manager
RadioLinx Intelligent Cellular Serial Modem for Global GPRS/GSM User Manual
Page 68 of 136 ProSoft Technology, Inc.
May 29, 2009
Because many cellular providers, like wire-based ISPs, do not offer static IP
addresses or static address accounts cost a premium vs. dynamic accounts, IP
Manager works with a Dynamic DNS server to receive notification from RLXIC
modems to translate the modem's dynamic IP address to a fully qualified domain
name. Thus, you can contact your RLXIC-SG directly from the Internet using a
domain name.
8.2 Understanding Domain Names
A domain name is a name of a server or device on the Internet which is
associated with an IP address. Similar to how the street address of your house is
one way to contact you and your phone number is another, both the IP address
and the domain name can be used to contact a server or device on the Internet.
While contacting you at your house address or with your phone number employ
different methods, using a domain name instead of the IP address actually uses
the same method, just a word based name is commonly easier to remember for
most people than a string of numbers.
Understanding the parts of a domain name can help to understand how IP
Manager works, and what you need to be able to configure the modem. A fully
qualified domain name (FQDN) generally has several parts.
 Top Level Domain (TLD): The TLD is the ending suffix for a domain name
(.com, .net, .org, etc.)
 Country Code Top Level Domain (ccTLD): This suffix is often used after the
TLD for most countries except the US (.ca, .uk, .au, etc.)
 Domain name: This is the name registered with ICANN (Internet Corporation
for Assigned Names and Numbers) or the registry for a the country of the
ccTLD (that is, if a domain is part of the .ca TLD, it would be registered with
the Canadian domain registry). It is necessary to have a name registered
before it can be used.
 Sub-domain or server name: A domain name can have many sub-domain
or server names associated with it. Sub-domains need to be registered with
the domain, but do not need to be registered with ICANN or any other
registry. It is the responsibility of a domain to keep track of its own subs.
server123.example.com
 .com is the TLD

example is the domain (usually noted as example.com, because the domain is
specific to the TLD)

server123 is the subdomain or server name associated with the device,
computer, or modem registered with example.com.
server123.example.com.ca
This would be the same as above, but with the addition of the country code. In
this example, the country code (.ca) is for Canada.