Monitoring
All of the servers in our SMTP cluster are monitored intensively. This is done in order to ensure that we do not overlook any issues that could potentially compromise out ability to deliver.

External services
Every day, we collect data concerning our deliveries from various external reputation databases. Doing so makes it possible for us to notice if a delivery issue appears in any server in the cluster. Here are a few examples of the databases monitored:
- Hotmail / Outlook: Smart Network Data Services
- ReturnPath: SenderScore
- Cisco: IronPort Email and Web Security (SenderBase)
- Watchguard: ReputationAuthority
- McAfee: Trusted Source
Additionally, we monitor over 200 different RBLs (Real-time Blackhole Lists).
SMTP reporting
All servers in our SMTP cluster report to our operations staff on a weekly basis. These reports contain information about general delivery speed and any delays caused by various blocking. This is displayed based on domain levels, which enables us to quickly gain a clear overview.
If we find any issues, these can most often be solved through minor adjustments in the setup of our SMTP-cluster - ensuring that we easily maintain the optimal delivery speed.
Performance
When a newsletter is sent from our system, it displays in our global statistics. This enables us to measure whether each newsletter performs at a level too askew from the general performance levels. These factors are monitored:
- View rates
- Click rates
- Bounce rates
- Junk rates (collected from our Feedback Loops)
This means that we can quickly spot potential misuse of our system. This way, we avoid that misuse can occur to a degree where the general performance might suffer.