| Feature | Proto Balance | Proto Balance Advanced | Proto Balance SSL | Proto Balance Mail |
| Low price | €39 | €149 | €269 | €65* |
| Thousands of concurrent connections |  | | | |
| Easy-to-use intuitive web interface | | | | |
| Load balancing by sender/recipient group |  | | | |
| Load balancing by round robin | | | | |
| Load balancing by least traffic | | | | |
| Load balancing by least connections | | | | |
| Load balancing by custom function | | | | |
| Load balancing by hash of client IP | | | | |
| Load balancing by pure random | | | | |
| Hot redirect clients to other server | | | | |
| Add new server machines on-the-fly | | | | |
| Factor multiplier for asymmetric loading | | | | |
| Return client to previously connected server | | | | |
| Transparent fallover to chosen server | | | | |
| Traffic accounting | | | | |
| Traffic graphs day/week/month | | | | |
| Table of connecting clients | | | | |
| Email user management system | | | | |
| Email password management system | | | | |
| XML/SOA interface for user provisioning | | | | |
| XML/SOA interface for server provisioning | | | | |
| SMTP AUTH support | | | | |
| POP support | | | | |
| Relay client address-range provisioning | | | | |
| Email alias support | | | | |
| Email alias management interface | | | | |
| Email alias XML/SOA interface | | | | |
| SPAM Greylisting protection | | | | |
| Per-user spam control settings | | | | |
| Auto-reply/out-of-office support | | | | |
| Auto-reply XML/SOA provisioning | | | | |
| Auto-blacklisting of bot-net clients | | | | |
| Auto-blacklisting of mal-ware users | | | | |
| Blacklist management interface | | | | |
| Blacklist XML/SOA management interface | | | | |
| Auto-whitelisting connected recipients | | | | |
| Per-email-user delivery/access stats | | | | |
| Account connection rate of clients | | | | |
| Config interface password restricted access | | | | |
| Secure admin cookie authentication | | | | |
| Layer 7 inspection of HTTP failures | | | | |
| Configurable connect timeout to servers | | | | |
| Display last server failure time and full error | | | | |
| Add X-Forwarded-For: HTTP header | | | | |
| Limit on client connection rate, configurable | | | | |
| Limit on max concurrent client connections | | | | |
| Configurable max time to hold client IPs | | | | |
| Configurable store size for client IPs | | | | |
| Denial of Service (DoS) protection | | | | |
| SSL/TLS terminator | | | | |
| SSL/TLS decryption and forwarding | | | | |
| SSL/TLS self-signed certificate generation | | | | |
| Auto-generation of certificate for testing | | | | |
| Certificate request generation | | | | |
| Importing of existing purchased certificates | | | | |
| Importing of web site private key | | | | |
| Password protection of private key | | | | |
| Supports PEM certificate format | | | | |
| Handle 1000 new SSL connections per sec | | | | |
| SSL session cache and resume | | | | |
| Cache millions of SSL sessions | | | | |
| SSL v2, SSL v3, TLS v1 support | | | | |
| SSL/TLS cipher support: RSA, AES, RC4 | | | | |
| SSL/TLS cipher support: DES, MD5, SHA | | | | |
