Barracudacentral.org – technical insight for security pros
Barracuda Status Block List (BRBL) – A Typical DNSBL Implementation
The Barracuda Status Block List (BRBL) relies on a standard DNSBL (Website Name System Block List) implementation you can use to lessen junk e-mail volume on the majority of popular email systems, including Microsoft Exchange, IBM Lotus Domino, sendmail, Postfix, and qmail, in addition to by many people antispam solutions like the Barracuda Junk e-mail & Virus Firewall. DNSBL systems list IP addresses, frequently individuals which have been observed through the list operator to become delivering junk e-mail or hosting spammers. With the addition of DNSBL records for an email server configuration, individuals email servers may either reject connection attempts from listed IP addresses or use that listing to use appropriate filtering policy.
DNSBLs are occasionally known as RBLs (Realtime Blackhole Lists), or simply BLs (Block/Black lists).
You should observe that a DNSBL cannot stop anybody from delivering email. A DNSBL only prevents delivery in the receiving finish in the receiver’s instruction. DNSBLs are strictly defensive tools, plus they canrrrt do any offensive damage for example denial and services information attacks.
Barracuda Status Block List (BRBL) – A Typical DNSBL Implementation
The Barracuda Status Block List (BRBL) relies on a standard DNSBL (Website Name System Block List) implementation you can use to lessen junk e-mail volume on the majority of popular email systems, including Microsoft Exchange, IBM Lotus Domino, sendmail, Postfix, and qmail, in addition to by many people antispam solutions like the Barracuda Junk e-mail & Virus Firewall. DNSBL systems list IP addresses, frequently individuals which have been observed through the list operator to become delivering junk e-mail or hosting spammers. With the addition of DNSBL records for an email server configuration, individuals email servers may either reject connection attempts from listed IP addresses or use that listing to use appropriate filtering policy.
DNSBLs are occasionally known as RBLs (Realtime Blackhole Lists), or simply BLs (Block/Black lists).
You should observe that a DNSBL cannot stop anybody from delivering email. A DNSBL only prevents delivery in the receiving finish in the receiver’s instruction. DNSBLs are strictly defensive tools, plus they canrrrt do any offensive damage for example denial and services information attacks.
Generally, DNSBL queries are structured through the inverse Ip like a subdomain from the DNSBL zone. For instance, to check on the general DNSBL test address of 127…2 shows up in BRBL, you are able to query 2…127.b.barracudacentral.org with any DNS lookup tool. Examples are below:
Linux/Unix systems:
$ host 2…127.b.barracudacentral.org
2…127.b.barracudacentral.org has address 127…2
Home windows systems:
C:>nslookup 2…127.b.barracudacentral.org
Server:
Address:
Non-authoritative answer:
Name: 2…127.b.barracudacentral.org
Address: 127…2
Resourse: http://barracudacentral.org/rbl/
