Blog | Securence - Part 5


DNSBLs and Securence Part 2: Securence Getting Listed on other DNSBLs

Securence provides outgoing email filtering and delivery. Most Securence customers are provided a dedicated IP address that no other customer will use. This isolates customers from potential IP reputation problems. If another customer sends spam or bulk emails, all other customers are protected from the IP reputation damage that may occur. This is a major advantage over other email services where emails are delivered from a pool of shared IP addresses. Although these services have many IP addresses in their pool, it’s possible to have these IP addresses’s reputations tainted because of the inevitable spam that will be sent through these services.

Most DNSBLs yellowlist the major email senders, but this is an imperfect practice and these IPs sometimes get listed or at least don’t enjoy a positive IP address reputation.

Automated services within Securence monitor all the outgoing IP addresses on major and minor IP reputation lists including Spamcop, Spamhaus, etc. When there are IP address reputation problems, our email team will investigate the cause and resolve it. Often this requires action by the customer’s email administrator. We assist and give helpful information to help resolve the issues quickly.

Once the root cause has been addressed, if the IP reputation is still poor, a new address is assigned and the previous one is retired. Retired IP addresses get set aside for a time to allow listings to expire. Before an IP address is reintroduced as a potential dedicated outgoing address, Securence admins ensure its reputation is neutral or positive.


DNSBLs and Securence Part 1: Securence’s Use of DNSBLs

DNSBL stands for DNS Block List. Also called RBL for Realtime Block List. These acronyms have had different words at times, but they generally do the same thing: prevent emails based on the IP address of the sending server.

Securence, by default, uses two of our own private DNSBLs and two independent DNSBLs to block messages based on IP address.

  • is a realtime block list, listings are fully automated and extremely short lived. Listings are intended to exist during a spam outbreak and expire as soon as the behavior stops. This uses a yellowlist to prevent blocking the major email senders. Though our support department has a delisting process, blocks have typically expired by the time our support department receives any delisting request.
  • is a non-realtime block list. This is a very small list of addresses and is manually curated by our email staff. Candidates are personally researched before listing to ensure no clean emails are originating from these addresses. Generally, listings do not expire. Though our support department has a very simple delisting process available, we have never received a delisting request.
  • Securence has subscriptions for Spamhaus and Spamcop. These lists are served from our internal servers and updated frequently from the providers. These are enabled by default for new domains and we recommend our customers to use both. They have their own processes and procedures that can be found on their respective web sites.
  • Securence can be configured to use any standard DNSBL in the admin portal. If you have a DNSBL you would like to use, go to Domain Settings->IncomingSettings->Spam->DNS Block Lists->Other DNS Block Lists or ask our support staff for assistance.