Realtime Black List & Greylisting


What is realtime black list(rbls)

RBLs uses the dns protocol to query the well-known IP addresses which have been complaint to send junk e-mail. Using RBLs to prevent the junk e-mail is very useful. RBLs is different with Anti-Spam service: RBLs blocks the junk e-mail based on the IP addresses; Anti-Spam service block the junk e-mail based on the message content. Using RBLs can save the resources of mail server.

Where can I find RBLs servers?

EmailArchitect server has several rbls servers set by default, but you can find more rbls servers by the following url:
https://www.robtex.com/?blacklists=1.

Recommended RBLs Servers:
bl.spamcop.net
zen.spamhaus.org
cbl.abuseat.org

Trusted SPF records

Because RBLs is not 100% correct, so using this option can prevent rbls block the normal message.

First of all, please learn more detail about Sender Policy Framework (SPF) by the following url:
http://www.openspf.org/

Therefore SPF is very good solutions to prevent faked email sender.

For exmaple: The email sender is: xxx@adminsystem.com and this email is from IP address: 210.17.235.64. By querying the dns server of adminsystem.com, mail.adminsystem.com is the MX record of adminsystem.com and the IP address of "mail.adminsystem.com" is "210.17.235.64", so there is enough reason to believe this email is not faked. And rbls will never block this IP address even this IP address is list on the rbls servers.

Because many spammers also set the SPF record, so do not put unknown domain to Trusted SPF/MX/A records.

Trusted IP Addresses

Put the following IP addresses to this list is recommended, it can prevent RBLs servers block the email from local LAN, Gmail and Hotmail:

127.0.*
192.168.*
10.1.*
172.16.*
::1
// Gmail
216.239.32.0/19
64.233.160.0/19
66.249.80.0/20
72.14.192.0/18
209.85.128.0/17
66.102.0.0/20
74.125.0.0/16
64.18.0.0/20
207.126.144.0/20
173.194.0.0/16
// Hotmail
209.240.192.0/19
65.52.0.0/14
131.107.0.0/16
157.54.0.0/15
157.56.0.0/14
157.60.0.0/16
167.220.0.0/16
204.79.135.0/24
204.79.188.0/24
204.79.252.0/24
207.46.0.0/16
199.2.137.0/24
199.103.90.0/23
204.182.144.0/24
204.255.244.0/23
206.138.168.0/21
64.4.0.0/18
65.54.128.0/17
207.68.128.0/18
207.68.192.0/20
207.82.250.0/23
207.82.252.0/23
209.1.112.0/23
209.185.128.0/23
209.185.130.0/23
209.185.240.0/22
216.32.180.0/22
216.32.240.0/22
216.33.148.0/22
216.33.151.0/24
216.33.236.0/22
216.33.240.0/22
216.200.206.0/24
204.95.96.0/20
65.59.232.0/23
65.59.234.0/24
209.1.15.0/24
64.41.193.0/24
216.34.51.0/24

Why RBLs blocks the local user to send email from dynamic IP addresses.

Now, more and more rbls servers list the dynamic IP addresses to prevent the bulk mailer to send junk e-mail. To let the local user to send email from dynamic IP addresses, the user must set the user authentication in e-mail client . If the user set the user authentication, the rbls will never block the connection.

Greylisting

Greylisting is a new weapon to use against spam in this great war being waged upon it. With this new shielding method, by which you may block out huge amounts of spam, you are sure to please your email clients!

To learn more detail about greylisting, please refer to http://www.greylisting.org/

By default, Greylisting is disabled in Emailarchitect Server, you can enable it in Web Access -> Services -> Realtime Black List -> have "Enable GreyList" checked and click "OK", and then Greylisting will be started. If this option is checked, even you stop "Realtime Black List" service, Greylisting still works except you disable it by having "Enable GreyList" unchecked.

Important Notice: Greylisting delays time to deliver the email to your local user. If you do not receive many junk emails, please do not enable it.

Trusted Sender

If the sender address is in user contacts or trusted email address, RBLS or Greylisting will never block the IP address/Sender.

See Also

Quick Tutorial  User Permissions  Domain Administration  User Administration  Services Administration  SMTP Service  POP3 Service  IMAP4 Service  Remote Object Call Service  Webmail Service  SSL Configuration  Realtime Black List  Anti-Spam  Anti-Virus  List Administration  Traffic Control  DBConnector  Mail Archive  DomainKeys and DKIM signature  Storage and User Mailbox   Incoming/outgoing Filters  Advanced Functions in Filter  Templates  

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