Nekaj zlatih pravil na katere moramo biti pozorni pri konfiguraciji poštnih strežnikov. / Some rules to be aware of when configuring mail servers.
DNS nivo / DNS layer

1. MX zapis mora obstajati / MX record must exist
Za test lahko v ukazni vrstici vpišete ukaz / For testing you can try to get the MX record using nslookup command:
nslookup
set type=MX
company.com
Kot rezultat bi morali dobiti / As result you should get:
company.com MX preference = 10, mail exchanger = mail.company.com

2. Forward in reverse DNS zapis se morata ujemati / Forward and reverse DNS record must be the same
Primer / Example:
Recimo, da MX zapis za domeno company.com kaže na poddomeno domene company.com in sicer na mail.company.com. V primeru, da izvršimo ukaz ping v ukazni vrstici dobimo rezultat: / Let say, that MX record for domain name company.com points to subdomain of company.com – mail.company.com. In this case you can check by pinging hostname and get the result:

C:\>ping mail.company.com
Pinging mail.company.com [123.123.123.123] with 32 bytes of data:
Reply from 123.123.123.123: bytes=32 time=119ms TTL=238 …

Ce pa izvršimo ukaz, ki nam iz IP naslova razreši DNS zapis moramo dobiti rezultat: / If we try to make a reverse lookup we should get the same result:

C:\>ping -a 123.123.123.123
Pinging mail.company.com [123.123.123.123] with 32 bytes of data:
Reply from 123.123.123.123: bytes=32 time=111ms TTL=238
…

Nivo poštnega strežnika (SMTP strežnika) / Mail server layer (SMTP server)

SMTP strežnik se mora oglasiti z istim imenom, kot je vpisan v MX zapisu – v našem primeru: mail.company.com. To pa lahko preizkušamo tako, da se z uporabo programa telnet povezemo na poštni strežnik na portu 25. / SMTP server should present with the same name as a name in MX record. In our case this is mail.company.com. This can be tested using telnet program connecting to port 25 of our mail server.
Kot rezultat bi morali dobiti: / As a result you should get:

220 mail.company.com Microsoft ESMTP MAIL Service, Version: 6.0.3790.1830 ready at Mon, 5 Feb 2007 23:07:34 +0100

http://www.dnsreport.com – preverite nastavitve svoje domen / check your domain name configuration
http://www.dnsstuff.com – dodatna orodja za pregled DNS zapisov / additional tools for checking DNS records
http://www.microsoft.com/mscorp/safety/content/technologies/senderid/wizard/ – Sender policy framework – generator TXT zapisa / Sender policy framework TXT record generator

  I. del / Part I. – Message delivery properties – general
(wink source) 

 II. del / Part II. – Message delivery properties – Connection filtering
(wink source) 

 III. del / Part III. – Message delivery properties – IMFv2 / Sender ID filtering
(wink source) 

 IV. del / Part IV. – Activate filters on SMTP server
(wink source) 

 V. del / Part V. – SMTP server name