Field

Description

Use DNSBL

Check this option to use DNSBL checking.

Use the B button to specify a list of IP addresses, domains and email address that you will not perform the DNSBL check for (effectively a list of trusted addresses).

Close connections for DNSBL sessions

Check this option and any connections from IP addresses which are listed on the blacklist will be closed immediately.

Host List

Here you must define a list of DNSBL server(s) you wish to query.

Use the Add and Delete buttons to populate and de-populate the list.

You can use as many DNSBLs as you wish but you should be aware that each query will add some processing time.

Reject if sender's IP has no rDNS

Check this option to enable rDNS (reverse DNS) checking.

Any connection from a server that does not have an rDNS record (PTR record) will be rejected.

Reject if originator's domain does not exist

Check this option to check for the existence of a DNS A record for an incoming message senders domain.

If the senders domain has no A record the message is rejected.

Field

Description

Enable SRS (Sender Rewriting Scheme)

Activates the SRS technology fixing the SPF forwarding mail issue, by forcing the agent to change the "mail from" address.

NOTE: When using SRS, it builds the MAIL FROM always referring to the primary domain. You may have a reason not to show your primary domain but still use this feature.

The solution is to have SRS enabled + enable the Use domain IP address for outgoing connection feature (Domains and Accounts – Global Settings – Domains – Other) or set the C_Accounts_Global_Domains_IPAddress API variable to 1.

Use SRS NDR (Non-Delivery Report) Validation

Activate this feature if you want server to validate whether incoming NDRs (bounce backs) contain the correct SRS hash (see SRS secret key). If not, these NDRs are not delivered into users' mail boxes.

SRS secret key

The secret key is any arbitrary string you can make up - it is your own passphrase. The secret key will be used for ciphering the data (for hash creation). This field must not be left blank.

The 'B' button

Use this button to open and edit the SRS bypass file srsbypass.dat.

See the example in the bypass file for the correct syntax.