High Availability

In addition to being able to seamlessly handle an MTA instance failure, the HLB configuration settings can be changed dynamically without requiring a restart. Adding and removing nodes, IP addresses, and ports can be done at any point with no downtime.


Because of the event-driven non-blocking I/O design of the LB it can easily handle hundreds of connections per second and thousands of simultaneous connections in a virtual environment. This means if you are currently getting 1 million message an hour with a single MTA, utilizing 3 MTA’s would allow you to process 3 times that much while still setting your application to submit to a single endpoint.

Real-Time Node Failover

Standard load balancers utilize a “heartbeat” check that pings each node and removes nodes from the cluster when a check fails. A common problem with this process is that connections are lost in the time between the node going down and the heartbeat detecting the failed node. This problem is resolved with the HLB as it detects connectivity problems in real time. If the HLB can’t connect to a node, it will continue to try each additional node until a connection can be made.

IP Address Preservation

Since the HLB communicates to the MTA using a proprietary protocol it can preserve the IP address, which allows the MTA to show the client’s IP address in the logs and headers instead of the LB’s IP address. This makes debugging multiple clients and setting up inbound restrictions/black listings based on the IP address possible.

SSL Termination

The HLB can allow SSL/TLS encrypted connections on one or more defined ports and route those to the MTA.

The Hurricane Load Balancer enables existing and new Hurricane MTA Server customers to deploy an effective high availability SMTP server network. For more information about Hurricane Load Balancer please contact our sales department.

SocketLabs Hurricane MTA is Trusted By:

Hurricane MTA Server has significantly improved our email delivery performance. In addition, the advanced reporting and logging features in Hurricane MTA Server have reduced the time required to investigate deliverability issues by at least 50 percent.

Christopher Harris  |  Email Specialist , Blackbaud

Hurricane MTA Server significantly increased our delivery rate. We generated more traffic to our sites and a greater return for our advertisers. More importantly we can keep our relationship with our readers alive retaining brand loyalty and future proofing our business.