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HOWTO Setup Internet SMTP Mail
The Network Concierge uses sendmail, a mail transport agent using the SMTP protocol. As an E-mail server the Network Concierge will send and receive mail via the Internet/Intranet on behalf of unlimited number attached client machines. E-mail setup is completely automated. All you have to do is setup users and their passwords in order for them to send and receive e-mail.
The following describes how to set up the Network Concierge for use as an Internet SMTP Mail server.
Requirements:
1. Internet access
q Dedicated (DSL, Cable, ISDN, Frame relay, Satellite, etc….)
q dial (56K analog, ISDN)
2. Registered domain name i.e. YourDomainName.com
3. Static IP address from your ISP i.e. 000.111.222.333
4. An agent to act as Primary Domain Name Server for your registered domain
5. A secondary mail server to spool mail when not connected to the Internet
The required services are usually provided by your Internet Service Provider (ISP) as part of your dedicated service or can be provided for an additional fee. For dial up service, Mail Spooling is highly recommended, while optional for dedicated service.
Things to do:
1. Enter the Static IP address (000.111.222.333) into the Internet Ethernet interface of the Network Concierge for a dedicated connection or the Internet Dial-out interface for a Dial-up connection to the Internet.
2. Have your (ISP) setup the following:
· Primary Domain Name Service (DNS) for your registered domain name (YourDomainName.com).
· Create Internet Address (A) and Mail Exchange (MX) records as part of the entries in the new created primary DNS for your registered domain (YourDomainName.com).
1. Create two Internet address (A) records using the static IP address 000.111.222.333 The same IP address used on the Internet interface of the Network Concierge.
· YourDomainName.com 000.111.222.333
· Mail.YourDomainName.com 000.111.222.333
2. Create two inverse address records for Domain name (YourDomainName.com) and the Network Concierge Internet interface (Mail.YourDomainName.com).
· 333.222.111.000 YourDomainName.com
· 333.222.111.000 Mail.YourDomainName.com
3. Create at least two Mail Exchange (MX) records
· The first MX record should contain the Mail.YourDomainName.com, an internal host name and the IP address used on the Internet interface of the Network Concierge. This (MX) entry should have a preference of 5 or some number lower than that used by the ISP (the lower the preference number the higher the priority).
· The next MX record should contain the name of the ISP Mail Spooling server with a preference number higher than that used for the previously setup (MX) record.
3. After you have completed setting up the Network Concierge and the ISP has setup the Primary DNS for your domain, you could verify your configuration by using an application such as NSLOOKUP.
An nslookup of your domain should look as follows:
> set q=a
> networkconcierge.com
Server: domain.server.com
Address: 192.247.246.1
Non-authoritative answer:
Name: networkconcierge.com
Address: 209.192.223.138
> mail.networkconcierge.com
Server: domain.server.com
Address: 198.207.206.1
Non-authoritative answer:
Name: mail.networkconcierge.com
Address: 000.111.222.333
> set q=mx
> networkconcierge.com
Server: domain.server.com
Address: 192.247.246.1
networkconcierge.com MX preference = 10, mail exchanger = mail.networkconcierge.com
networkconcierge.com MX preference = 20, mail exchanger = relay1.isp.net
networkconcierge.com MX preference = 20, mail exchanger = relay2.isp.net
networkconcierge.com nameserver = ns1.isp.net
networkconcierge.com nameserver = ns2.isp.net
networkconcierge.com nameserver = ns3.isp.net
networkconcierge.com nameserver = ns4.isp.net
mail.networkconcierge.com internet address = 000.111.222.333
relay1.isp.net internet address = 72.244.124.129
relay2.isp.net internet address = 72.244.124.137
ns1.isp.net internet address = 192.168.85.129
ns2.isp.net internet address = 192.168.145.5
ns3.isp.net internet address = 192.168.145.6
ns4.isp.net internet address = 192.168.85.21
4. With your configuration verified setup your POP3 clients (Eudora, Outlook express, Netscape mail, etc.), using the parameters below:
· Incoming mail (POP3): mail.networkconcierge.com
· Outgoing mail (SMTP): mail.networkconcierge.com
· User name: User_name created on Network Concierge
· Password: Password used when User_name created on Network Concierge
SMTP
SMTP is an electronic mail protocol used by Internet/intranet based email
servers and gateways to exchange messages.
SMTP is a 'push' protocol. Whenever an SMTP server or gateway has a message
to send, it establishes an SMTP session with the destination server or
gateway and then transmits ('pushes') one or more messages. The receiving
server or gateway must be 'listening' for an SMTP connection request. If the
destination SMTP server or gateway is not attached to the Internet/intranet,
message exchange is not possible. The transmitting server or gateway will
repeatedly try to connect to the destination server or gateway. After a
certain number of failed attempts the message will be discarded.
SMTP is well suited for servers or gateways that are continuously attached
(using a dedicated connection) to the Internet/intranet. Servers or gateways
that are not continuously attached (using a dedicated dial-up connection) to
the Internet/intranet may use SMTP but they must attach to the
Internet/intranet for sufficient periods of time (usually hours). This is to
ensure that they are available to any server or gateway trying or retrying
to send it messages. Dedicated dial-up SMTP, therefore, is not efficient
because a connection needs to be maintained even when messages are not being
transferred. You pay for the connection time and need a telephone line that
cannot be used for any other purpose (i.e. shared with fax machine or
individuals surfing the Internet). Some SMTP servers support ways of
triggering them to start sending mail to a specific domain. If your ISP
supports this feature then the dial-up connection need only be maintained
while messages are being exchanged.
SMTP Spooling (Mailbagging)
For a dedicated Internet connection, the SMTP protocol presents no problems.
However, for a dial-up connection, where the server or gateway is not always
connected to the Internet, the server or gateway will often be unavailable
to receive incoming mail.
To address this problem, some Internet Service Providers provide a service
called SMTP Mailbagging. All messages destined for your domain are
temporarily stored on your Internet Service Provider's SMTP host. When your
server or gateway connects, it issues a special command to your ISP's SMTP
host to notify it that your server or gateway is now available to receive
its messages.
The signaling method varies from ISP to ISP. Signaling methods include, but
are not limited to, using the ETRN command in the extended SMTP protocol or
sending a FINGER command to the ISP's host with your domain as the argument.
DNS
Domain Name Service (DNS) is used to determine the physical Internet address
(IP address) for a domain's mail host such that a server or gateway can
connect and send it mail. DNS is a service that maintains a database of host
names, IP addresses, and domains. DNS also stores information like domain
name aliases and mail routing records (called MX records). If a DNS server
is available (usually at your Internet Server Provider's site), the gateway
can request from it a domain's mail host and network address.
POP3 Server
A POP3 server receives and stores e-mail messages on behalf of its users.
Its users can connect to the server using Internet/intranet clients (that
support the POP3 protocol) and retrieve their messages. Users may also send
messages via the server (using SMTP).
POP3
POP3 is an electronic mail protocol used to retrieve messages stored on an
Internet/intranet e-mail server.
POP3 is a 'pull' protocol. Whenever a client wants to check for messages it
connects to its Internet Service Provider's e-mail server and uses POP3 to
login to its mailbox and 'pull' down its messages.
POP3 is well suited for dial-up environments because the client need not be
attached to the Internet/intranet when another user is trying to send it
mail. The mail arrives at the server and is stored in the user's mailbox.
The server is always available on the Internet/intranet to receive mail. The
client can dial-up and attach to the server at a later time to retrieve its
messages.
The dial-up connection is only active while messages are being exchanged
which is cost-effective and allows the telephone line to be shared by a fax
machine. When the connection is active, outbound messages are also sent
(using the STMP protocol).
MX (Mail exchange) resource record
MX records specify a list of mail servers that are configured to receive mail sent to this domain name. Every mail server that receives mail for a domain should have an MX record.
NSLOOKUP
NSLOOKUP is a utility that performs domain name to IP address (forward DNS lookup), IP address to domain name (reverse DNS lookup) and mail exchange.
