SMTP server vs MAIL server

[kenghtt]

I'm very new to this stuff. What is the difference? and would I need both to get a mail server working?

 

[casper1973]

SMTP server handles outgoing mail (ie. it sends your mail out).

"Mail Server" is more of a general term. At the basic level it means something that collects mail, processes it, then "serves" it out to clients. It could host a simple POP3 service or it could host everything from POP3, IMAP, SMTP, Exchange services.

 

[Pinhedd]

I'm very new to this stuff. What is the difference? and would I need both to get a mail server working?

Hi there,

SMTP is a mail transmission protocol. It is used to send mail to a destination, either lazily (sending it directly to the mail exchanger for the destination domain) or through an outbound mail relay server. The latter is the preferred method as lazily sent messages are often flagged as spam.

SMTP is not a mailbox protocol. It is implied from above that SMTP is for delivery only, and this is indeed the case. There are several other protocols that are used for mail retrieval, the process of retrieving email stored on a mail server. The most common ones are Post Office Protocol Version 3 (POP3) and Internet Message Access Protocol (IMAP).

Where as SMTP is suitable for only delivery, POP/IMAP are suitable for only retrieval. An SMTP client and SMTP server can stand alone on an outbound-only mail server or as part of a lazy transmission program (included in some web frameworks) but POP and IMAP servers are useless on their own, they need to be paired with a mail server that pulls the SMTP and POP/IMAP protocols together.

There are a number of different mail server suites around, some are free but most are not. Mail servers combine implementations of all the various mail protocols together (a protocol on its own is abstract) into one big functional package and sprinkle a large number of goodies on top. At a minimum a mail server includes an SMTP implementation which allows the server to relay SMTP messages from authorized clients. More often the mail server also includes a mailbox program that allows the server to receive email (as opposed to simply relaying it), and implementations of the POP/IMAP protocols that allow clients to retrieve that email. Email servers also often include message filtering, spam filtering, quota control, shared calendars, shared address books, shared storage space, and many more features.

If you're interested in setting up your own mail server I would recommend SmarterMail as a good place to get started. It's best in class next to Microsoft Exchange and it does have a fully functioning free version that is limited only by the number of domains and mailboxes (1 domain, 10 mailboxes; enough for a family). I've been using it for many years for my family's email accounts, it's quite easy to get started with and has a purely web-based administrative interface.

 

[kenghtt]

I'm very new to this stuff. What is the difference? and would I need both to get a mail server working?

Hi there,

SMTP is a mail transmission protocol. It is used to send mail to a destination, either lazily (sending it directly to the mail exchanger for the destination domain) or through an outbound mail relay server. The latter is the preferred method as lazily sent messages are often flagged as spam.

SMTP is not a mailbox protocol. It is implied from above that SMTP is for delivery only, and this is indeed the case. There are several other protocols that are used for mail retrieval, the process of retrieving email stored on a mail server. The most common ones are Post Office Protocol Version 3 (POP3) and Internet Message Access Protocol (IMAP).

Where as SMTP is suitable for only delivery, POP/IMAP are suitable for only retrieval. An SMTP client and SMTP server can stand alone on an outbound-only mail server or as part of a lazy transmission program (included in some web frameworks) but POP and IMAP servers are useless on their own, they need to be paired with a mail server that pulls the SMTP and POP/IMAP protocols together.

There are a number of different mail server suites around, some are free but most are not. Mail servers combine implementations of all the various mail protocols together (a protocol on its own is abstract) into one big functional package and sprinkle a large number of goodies on top. At a minimum a mail server includes an SMTP implementation which allows the server to relay SMTP messages from authorized clients. More often the mail server also includes a mailbox program that allows the server to receive email (as opposed to simply relaying it), and implementations of the POP/IMAP protocols that allow clients to retrieve that email. Email servers also often include message filtering, spam filtering, quota control, shared calendars, shared address books, shared storage space, and many more features.

If you're interested in setting up your own mail server I would recommend SmarterMail as a good place to get started. It's best in class next to Microsoft Exchange and it does have a fully functioning free version that is limited only by the number of domains and mailboxes (1 domain, 10 mailboxes; enough for a family). I've been using it for many years for my family's email accounts, it's quite easy to get started with and has a purely web-based administrative interface.

Thankyou so much for your input.
So in order to actually send and receive email, I must have both SMTP and POP3/IMAP in order to get it to work?
And you said that there are alot of different kinds of Mail Server. Would Mozilla Thunderbird work? My partners and I were trying to get it to work with Thunderbird, but havnt had any luck yet. Otherwise I could try SmarterMail.

 

[Pinhedd]

I'm very new to this stuff. What is the difference? and would I need both to get a mail server working?

Hi there,

SMTP is a mail transmission protocol. It is used to send mail to a destination, either lazily (sending it directly to the mail exchanger for the destination domain) or through an outbound mail relay server. The latter is the preferred method as lazily sent messages are often flagged as spam.

SMTP is not a mailbox protocol. It is implied from above that SMTP is for delivery only, and this is indeed the case. There are several other protocols that are used for mail retrieval, the process of retrieving email stored on a mail server. The most common ones are Post Office Protocol Version 3 (POP3) and Internet Message Access Protocol (IMAP).

Where as SMTP is suitable for only delivery, POP/IMAP are suitable for only retrieval. An SMTP client and SMTP server can stand alone on an outbound-only mail server or as part of a lazy transmission program (included in some web frameworks) but POP and IMAP servers are useless on their own, they need to be paired with a mail server that pulls the SMTP and POP/IMAP protocols together.

There are a number of different mail server suites around, some are free but most are not. Mail servers combine implementations of all the various mail protocols together (a protocol on its own is abstract) into one big functional package and sprinkle a large number of goodies on top. At a minimum a mail server includes an SMTP implementation which allows the server to relay SMTP messages from authorized clients. More often the mail server also includes a mailbox program that allows the server to receive email (as opposed to simply relaying it), and implementations of the POP/IMAP protocols that allow clients to retrieve that email. Email servers also often include message filtering, spam filtering, quota control, shared calendars, shared address books, shared storage space, and many more features.

If you're interested in setting up your own mail server I would recommend SmarterMail as a good place to get started. It's best in class next to Microsoft Exchange and it does have a fully functioning free version that is limited only by the number of domains and mailboxes (1 domain, 10 mailboxes; enough for a family). I've been using it for many years for my family's email accounts, it's quite easy to get started with and has a purely web-based administrative interface.

Thankyou so much for your input.
So in order to actually send and receive email, I must have both SMTP and POP3/IMAP in order to get it to work?
And you said that there are alot of different kinds of Mail Server. Would Mozilla Thunderbird work? My partners and I were trying to get it to work with Thunderbird, but havnt had any luck yet. Otherwise I could try SmarterMail.

There are three basic mail server configurations.

Send only

Receive Only

Send/Receive

A mail server configuration that only sends mail (or relays it on behalf of another sender) an implementation of the SMTP protocol. These are pretty common for websites that send out email notifications. The same domain may have an inbound mail server as well for mail sent to that domain, but it is often a different mail server. A mail server configured as a dedicated sender is designated an "outbound mail server" and is commonly named smtp.example.com

A mail server configuration that acts only as a final destination for domains that have mailboxes on that server (the server does not send or relay any mail) must have an SMTP protocol implementation at some point to be able to receive mail that is destined for mailboxes on that server. It must also have a POP3/IMAP protocol implementation (or an implementation of a proprietary protocol such as GMail or Microsoft Exchange) to allow clients to connect to the server and retrieve the contents of their mailboxes. A mail servers configured as dedicated receiver is designated an "inbound mail server" and is commonly named pop3.example.com or imap.example.com

A mail server that allows mail to flow in both directions is simply designated as a "mail server" and is commonly named mail.example.com.

Most popular email servers include all the protocols and allow administrators to enable them or disable them as desired.

The separation of outbound and inbound mail servers is common in larger networks and is considered best practices at larger enterprises. However, in smaller deployments it is common to combine them. ISPs in particular separate inbound and outbound mail servers as they commonly force all SMTP traffic on port 25 (the default SMTP port) on their own networks to be relayed through their own mail servers. This is done to prevent customers from sending spam to other networks, intentionally or otherwise. This can cause problems with domains that require all mail addressed from a domain to be relayed through that domain's outbound mail servers. If an employee works from home, sending work emails may be problematic.
For example, say that an employee sends email from the mailbox user@domain.com. Normally outbound mail from this domain is relayed through the SMTP server smtp.domain.com and inbound mail is delivered to mail.domain.com. There are provisions in email configuration to check if a mail server is authorized to send email on behalf of a domain. This is done to cut down on forgery. If these restrictions are lax, anyone could send an email from user@domain.com. If they are tight, forgery is harder but so is sending legitimate email. If the user sends email from home through his or her ISP's SMTP server which has the hostname smtp.example.com, emails from user@domain.com will appear to have been sent by the mail server smtp.example.com rather than the expected mail server smtp.domain.com. As a result it is common to provide a secondary SMTP port to get around ISP restrictions.

Mozilla Thunderbird is an email client, not an email server. It's a tool that can send mail through an SMTP server using the SMTP protocol, or it can receive email using the IMAP/POP3 protocols. Users may use any number of mail clients such as Mozilla Thunderbird and Microsoft Outlook, or they may use the web interface that's included with most comprehensive mail servers (SmarterMail includes one that is quite nice). These web interfaces are very similar to the likes of Hotmail and GMail.