Chapter 3. ServiceLink
•Guaranteed E-mail
This service provides a backup e-mail service if a server becomes unreachable and cannot receive mail. The most common reason for this is a temporary failure of the Internet connection provided by your ISP. With ServiceLink, mail that cannot be delivered to your server will be stored at the NOC. Simultaneously, notifications are sent to your Mitel Authorized Partner, who can investigate the cause of the outage.
This service uses what is called an MX secondary. Every domain name on the Internet has a record in the DNS which indicates which system should act as its primary mail exchanger ("MX" for short). When someone sends an e-mail, his or her local mail server will look for the recipient's MX and send the e-mail to it. If the MX is unreachable due to a system or network outage, the mail may be queued or it may bounce back to the sender.
The guaranteed e-mail service provided to ServiceLink subscribers works by configuring the DNS to use the NOC as a secondary MX. Therefore, if the primary MX is unreachable, the sender's mail server will send the e-mail to the secondary MX – in this case, the NOC. All e-mail collected in this fashion will be forwarded to your server as it becomes available again.
There is nothing that needs to be done to configure the guaranteed e-mail service. As soon as the NOC starts publishing your domain through the DNS service, the NOC will be set up to act as an MX secondary and start guaranteeing the delivery of your e-mail.
In addition to storing the e-mail and eventually forwarding it, the Mitel Networks NOC provides notification and reporting to your Mitel Authorized Partner. This allows your Partner to identify potential server or network outages at your site and respond in a timely fashion.
•DNS Services
One of the components of a full Internet solution is a domain name. Most businesses using the SME Server V5 with ServiceLink will want to register a domain name representing their business, and will need a DNS host to make this domain name accessible to the world.
For reasons of security and reliability, the server is not configured to publish DNS records by itself. (Any network server can be configured to act as a public DNS server, but doing so can create a serious security vulnerability.) A properly administered DNS host needs to be stable and always on the Internet, which is why a Network Operations Center such as that of Mitel Networks Corporation is ideally suited to the task.
The domain name hosting service provided by ServiceLink allows you to publish domain name records via our NOC. In addition to any domain names you may have registered, you will also be able to use the special e-smith.netdomain. This provides a low-cost alternative for small businesses or home users who do not wish to pay registration fees for a .com or other domain. Users may register their server with a name such as "mycompany.e-smith.net".
•IPSEC VPNs
As discussed in the section on remote access, your server provides support for client-to-serverVirtual Private Networks (VPNs) using PPTP. ServiceLink provides the additional ability to create server-to-serverVPNs using the highly secure IPSEC standard. This service allows you to link together servers in different physical locations to make one seamless "virtual" network. Information sent via this network is encrypted to prevent "snooping" by others on the Internet.
To encrypt network traffic between servers, the server uses the IPSEC protocol. This system uses an encryption technique known as public key cryptography. In simple terms, each server connected in a VPN knows the public key of each of the other servers on
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