Using your own SMTP server has advantages over POP3 such as reliable BCC handling, instant delivery of emails, and ability to block spam and viruses before delivery. However, it requires a constant internet connection and dynamic IP addresses can cause issues if the IP changes and emails are delivered to the wrong address temporarily. It is not recommended if the internet connection is unstable or the server computer frequently crashes.

1. Article on SMPT (standard mail transfer protocol)
Pros:
An SMTP server for reception, and a DynDNS utility for using a dynamic-IP DNS
provider like dyndns.org or selfhost.de.
Why SMTP?
Using your own SMTP server (standard mail transfer protocol) for e-mail
reception instead of retrieving mails from a POP3 mailbox has pros and cons
Let's look at the brighter side first.
Correct BCC handling: If somebody sends you a copy (BCC) of an e-mail, it
depends on non-standard header lines inserted by the POP3 server ,if it is still
possible to identify the correct recipient. It works sometime; receiving mail with
your own SMTP server is the only source to receive BCC-addressed mails
reliably.

2. Instant delivery: While you have to poll your e-mails every ten or fifteen
minutes using a POP3 account, an SMTP server receive incoming mails within no
time after being sent. E-mail received fast as chat!
Bounces to true sender: If an e-mail is denied, the SMTP server will bounce it to
the real sender regardless of the possibility that the from address isn't right
(which is for viruses & spam), while a arrival mail would go to another person.
Less data volume: Since the SMTP server has full hold over data it
acknowledges and which not, it can dismiss mail which goes to non-existing
client names, originates from banned IPs, or is somehow suspicious. This
decreases the traffic volume essentially and leaves more data transmission for
different applications such as web browsing.
Easy user management: Since catch all POP3 records are currently frequently
victims of address spam and virus attacks (with dream characters before @your-
domain), mailbox names must be arranged at two spots - at your supplier and in
you’re nearby email framework. At the point when using your own particular
SMTP server for reception, it can check valid usernames locally and square
invalid ones.
Better virus and spam protection: Using a DNS-based real-time black hole list
(RBL) and a list with expressly banned IP ranges of spam-accommodating
remote nations (you know their names!), you can block numerous spam and
virus senders even before their payload is exchanged to your framework. Your
mail acceptance policy can be superbly adjusted to your own needs, which would
never be workable for a POP3 post box at an ISP (Internet service supplier).
Obscure User: The SMTP server acknowledges legitimate user records and false
names as it were.
HTTP asks for: Some spammers use HTTP solicitations to proxy through the
SMTP port. They are detached instantly to stay away from a superfluous wrong
catch up dialog.
Cons:
Why not?
As expressed above, running your own particular SMTP server for email
reception requires all day, 2/7 Internet connection. Subsequent to most DSL/link
lines have dynamic IP addresses, this might bring about some unforeseen issues.
IP change: Most DSL or link suppliers detach the line once per day, typically
after 24 hours. It is a smart thought to force a distinction around evening time to
maintain a strategic distance from this amid business hours. In the event that
you don't claim a static IP address, another person - who now gets your old IP -

3. may get your messages until you enroll another IP at the DNS supplier. (This is
not likely, however, and regardless of the fact that it happens, an accurately
designed outsider server won't acknowledge sends to your area yet reply
"transferring denied.)"
DSL or PC failure: Comparative issues happen if your PC is down, of your local
DSL/cable line is out of service. (However, even then you will most probably not
lose any mails since the sending server will retry them for a few hours or even
days.)
The logical outcome is that you ought not run your own SMTP service if your DSL
or link connection is unstable, if you often have power outages, or if the server
PC is much of the time utilized for running unsteady applications, which at times
crash the operating framework. Additionally, not all Internet service suppliers
offer a configurable MX (mail trade) DNS record for hosted domains. Setting the
MX record to a different domain (ordinarily a DynDNS subdomain) is an
essential for running your own SMTP server for mail reception
Source File: http://www.shamrock-software.eu/dsl-smtp.htm