Dynamic Host Configuration Protocol (DHCP) is a protocol used by networked devices (clients) to obtain the parameters necessary for operation in an Internet Protocol network. This protocol reduces system administration workload, allowing devices to be added to the network with little or no manual configurations.
Dynamic Host Configuration Protocol is a way to manage network parameter assignment from a single DHCP server, or a group of DHCP servers arranged in a fault-tolerant manner. Even in small networks, Dynamic Host Configuration Protocol is useful because it can make it easy to add new machines to the local network.
DHCP is also recommended even in the case of servers whose addresses rarely change, so that if a server needs to be readdressed (RFC2071), changes can be made in as few places as possible. For devices such as routers and firewalls, that should not use DHCP, it can be useful to put Trivial File Transfer Protocol (TFTP) or SSH servers on the same machine that runs DHCP, which also serves to centralize administration.
DHCP can be used to assign addresses directly to servers and desktop machines, and, through a Point-to-Point Protocol (PPP) proxy, to dialup and broadband on-demand hosts, as well as for residential Network address translation (NAT) gateways and routers. DHCP is generally not appropriate for infrastructure such as non-edge routers and DNS servers.
Tuesday, July 29, 2008
Dynamic Host Computer Protocol (DHCP) Tutorials
Wednesday, July 23, 2008
E-mail hosting service
An email hosting service is an Internet hosting service that runs email servers.
Email hosting services usually offer premium email at a cost as opposed to advertising supported free Email Support or free webmail. Email hosting services thus differ from typical end-user email providers such as webmail sites. They cater mostly to demanding email users and Small and Mid Size (SME) businesses, while larger enterprises usually run their own email hosting service. Email hosting providers allow for premium email services along with custom configurations and large number of accounts. In addition, hosting providers manage user's own domain name, including any email authentication scheme that the domain owner wishes to enforce in order to convey the meaning that using a specific domain name identifies and qualifies email senders.
Most email hosting providers offer advanced premium email solutions hosted on dedicated custom email platforms. The technology and offerings of different email hosting providers can therefore vary with different needs. Email offered by most webhosting companies is usually more basic standardized POP3 based email and webmail based on open source webmail applications like Horde or Squirrelmail. Almost all webhosting providers offer standard basic email while not all email hosting providers offer webhosting.
Thursday, July 17, 2008
Email Troubleshooting Tutorial
Email seems simple, but email delivery can fail at any number of places in its journey from the MUA (mail user agent) of the sender to the MUAs of the intended recipients. Delivery may be delayed in a mail queue somewhere in the network cloud, may fail because the email was deleted by a spam filter or rejected for being over file-size limits or having the wrong MIME type content...or the user may be embarrasses to realize that the email that mysteriously vanished is still sitting in their outbox.
Messages sent to mailing lists can be unexpectedly rejected or sent to moderation queues because the sender doesn't understand posting rules, which can vary from list to list and depend on how the sender is classified by each mailing list. Generally, the privilege of direct posting is limited to certain classes of known users to protect the list from spam. Users may think something is wrong when they are unable to post directly to a list when they are actually using a different account from the one under which the posting privileges were granted.
The need to troubleshoot email isn't limited to apparent delivery failure or delays. Sometimes users receive automated email messages they don't understand, or sometimes inappropriate messages get posted to a list.
The existence of so many variables yields so many potential failure points that even though email seems simple in principal, troubleshooting email is an inherently complex process. In the interests of empowering everyone in the online community who would like to understand more about email Support and possibly troubleshoot email themselves, this documentation addresses a wide audience from users experiencing issues when posting to a mailing list to mailing list administrators and site managers. It covers a broad range of topics specific to troubleshooting email but references material scattered throughout the Concepts, Appendix and Tools page help. The purpose of this introduction is to help you get a birds-eye-view of the available documentation, some suggestions as to what might be of most interest to you (depending on whether you are a website user or administrator), plus some pointers that we hope will guide you along the fastest path to the information you need to resolve your issue.
Tuesday, July 8, 2008
E-mail hosting service
An email hosting service is an Internet hosting service that runs email servers.
Email hosting services usually offer premium email at a cost as opposed to advertising supported free email or free webmail. Email hosting services thus differ from typical end-user email providers such as webmail sites. They cater mostly to demanding email users and Small and Mid Size (SME) businesses, while larger enterprises usually run their own email hosting service. Email hosting providers allow for premium email services and Email Support along with custom configurations and large number of accounts. In addition, hosting providers manage user's own domain name, including any email authentication scheme that the domain owner wishes to enforce in order to convey the meaning that using a specific domain name identifies and qualifies email senders.
Most email hosting providers offer advanced premium email solutions hosted on dedicated custom email platforms. The technology and offerings of different email hosting providers can therefore vary with different needs. Email offered by most webhosting companies is usually more basic standardized POP3 based email and webmail based on open source webmail applications like Horde or Squirrelmail. Almost all webhosting providers offer standard basic email while not all email hosting providers offer webhosting.
Thursday, June 26, 2008
DNS hosting service
A DNS hosting service is a service that runs Domain Name System servers. Most, but not all, domain name registrars include DNS hosting service with registration. Free DNS hosting services also exist. Almost all DNS hosting services are "shared"; except for the most popular Internet sites, there is no need to dedicate a server to hosting DNS for a single website. Many third-party DNS hosting services provide Dynamic DNS.
DNS hosting service is better when the provider has multiple servers in various geographic locations that minimize latency for clients around the world.
DNS can also be self-hosted by running DNS software on generic Internet hosting services.
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Monday, June 16, 2008
Dynamic DNS and NAT
There has been tremendous growth in the use of Network Address Translation (NAT) functionality. These devices include Windows machines running Internet Connection Sharing, included in Windows 98SE/Me/2000/XP, or other similar software such as Sygate Home Network. NAT software is also included in most open-source operating systems such as Linux (IP masquerading) or FreeBSD (natd), and is available for other platforms, such as Vicomsoft's Internet Gateway for Macs. More recently, we have seen hardware devices, often referred to as "routers", implementing NAT functionality, such as the Linksys routers, the Netgear Internet Gateway Routers, or the Nexland ISB line.
Many users of various NAT implementations then wonder if it is still possible to use dynamic DNS technology, as implemented in our Dynamic DNS and Custom DNS services, when using NAT. By itself, NAT does not affect dynamic DNS that much, but it does have significant impact on the operation of servers, which is the primary motive for the use of dynamic DNS technology. This white paper will discuss these issues and, whenever possible, make recommendations as to how they can be dealt with. Please note that we do not endorse or provide support for any third-party products that may be mentioned in this article. Also, please note that our discussion of NAT will be limited to the type of NAT where one or more private IPs are converted to one public IP: there are other types of NAT out there, but they are not commonly used in the residential, home office, or small business market.
There are two main challenges involved with using NAT and operating servers with the help of dynamic DNS: ensuring that traffic actually makes it through the NAT and then ensuring that the dynamic DNS hostname/domain is properly updated.
If you are facing any network problem you can contact for Online Email Support and fixing you computer problem get Computer Help.
Tuesday, June 10, 2008
The Structure of a Domain Name
A domain name always has two or more parts separated by dots and typically consists of some form of an organization's name and a three letter or more suffix. For example, the domain name for IBM is "ibm.com"; the United Nations is "un.org."
aero--For the air-transport industry
.biz--Reserved for businesses
.com--For businesses, commercial enterprises, or online services like America Online. Most companies use this extension.
.coop--Reserved for cooperatives
.edu--For educational institutions and universities
.gov--Reserved for
.info--For all uses
.int--For organizations established by international treaties
.mil--For the
.museum--For use by museums
.name--For use by individuals
.net--For networks; usually reserved for organizations such as Internet service providers
.org--For non-commercial organizations
.pro--For use by professionals, such as attorneys and physicians
ICANN, the Internet Corporation for Assigned Names and Numbers, manages the Domain Name System. For the latest news, visit the ICANN website. The more popular TLDs (.com, .net, .org, .biz, .info, .name) are available to the general public for registration of domain names.
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