Like ISPs and hosting companies, ESPs save costs by sharing as much of their infrastructure between their customers, which will mean delivering mail out of shared IP addresses and shared tracking domains.
These IPs and domains have their own reputation. If poor reputation is attributed to these IPs and domains, it can cause issues for other customers. Keep in mind that one compromised account in your network can negatively impact your other customers.
Customer A, B, and C share the same IP.
Customer A is causing one of the ESPs outbound IPs to be blocked.
This blocking will then negatively affect customers B and C, as they share the same IP.
ESPs work very hard in most cases to ensure that this does not happen, e.g. they will have their in-house anti-abuse mechanisms, like looking for warning signs in address lists provided by new customers, running background checks, etc.
In this blog post, we mention a few best practices on how ESPs can improve email deliverability.
On top of the mechanisms mentioned above, ESPs can use several sets of blocklists as an additional outbound protection layer to improve email deliverability cost-effectively. By doing so, ESPs can maintain their IP reputation and ensure reliable email delivery.
Who can make use of Abusix’s outbound protection?
It’s not just ESPs that can make use of that additional outbound filtering with Abusix Mail Intelligence.
It is anyone, provided their MTA has post-authentication hooks where the connecting IP address can be checked and some sort of content filtering.
We recommend rSpamD, as it supports all of our blocklists and can utilize our “domain blocklist” and each of the various hash blocklists to find phishing, malware, and other malicious content before sending.
Which Blocklists Should I Use?
The specifically designed “authentication blocklist” can be used as an additional layer for your outbound protection. This blocklist can identify compromised accounts, as it tracks IPs that we have seen within our spam traps abusing other services.
ESPs can quickly improve their email deliverability by adding an outbound protection layer with Abusix Mail Intelligence.
On top of using our authentication blocklist, which is designed to spot compromised accounts in your network, we recommend using a content scanner like rSpamD to evaluate its spam score for further content filtering.
This content scanner can utilize our domain blocklist and each of the various hash blocklists to find phishing, malware, and other malicious content before sending.
If you’re interested in finding out more, please contact [email protected]