MailNexus Technical Overview
MailNexus has been recognized repeatedly as an industry leader for its ability to stay ahead of messaging and collaboration trends, while delivering a completely secure, reliable, and scalable hosted solution. Our primary goal is to ensure that all of our end-users receive the highest levels of performance and accessibility.
Carrier-Class Infrastructure
MailNexus's infrastructure was designed to provide carrier-class performance, scalability, and reliability to millions of users. Our datacenters are housed in Tier 4 facilities with high-availability fail-over server clusters, and 24x7x365 monitoring to ensure the security of all customer data.
Multiple Client Support
MailNexus's advanced architecture allows end-users to connect via our award-winning AJAX web client, via POP3 or IMAP4 desktop clients like Microsoft OutlookTM, or via their WAP 2.0-enabled mobile devices. Through our DirectConnect plug-in, MailNexus users can even maintain full sync between MailNexus online and Outlook on the desktop. No special hardware or software is required to use MailNexus. Our web client currently supports all popular Java-enabled Web browsers, including Firefox 1.5/2.0 (Windows, Mac OSX, and Linux), Microsoft Internet Explorer 5.0 - 7.0 (Windows).
Industry-Leading Spam & Virus Protection
MailNexus uses a multi-tiered approach to filtering unwanted junk and virus-ridden email. Sophisticated RFC compliancy verification systems placed at the perimeter of the mail exchange infrastructure detect and rejectmail destined to MailNexus accounts which: contain invalid header information; connect from "spam sources;" and/or do not follow standard protocol and communication procedures during message handoff. Messageswhich appear to come from valid sources and comply with all standard protocol requirements are then passed to MailNexus's anti-virus cluster.
This cluster, powered by ClamAV™, contains the latest virus definition files and scanning engines (updated 24 times per day, or once per hour) to ensure the virus outbreaks are contained immediately upon receipt of virus signatures. Message attachments and body content is scanned for various viruses, as well as rogue HTML or scripting code within the body of the message that may invoke security vulnerabilities within web applications and desktop mail utilities.All messages passing virus scanning mechanisms are then processed by our anti-spam cluster. This cluster, powered by SpamAssassin™, contains an intricate, highly modified set of spam signatures, content rules and body verifications. Using a scoring algorithm, the system automatically determines the status of the message (spam or valid) and the message is then processed and delivered to the user based on their junk mail control preferences.
Server-Side Spam Controls
Multiple RBL Lookups: MailNexus blocks mail from any sender that is on the MailNexus Real-time Blackhole List. MailNexus’s RBL list is built in real-time as our user community marks messages as spam. Alogrithms to ensure false positives are reduced automatically determine if a sender (IP based) should be added to the list, and for what duration. In addition to custom RBLs, MailNexus utilizes commercially available RBLs such as SpamCOP to provide additional layers of protection.
Relay Blocking: MailNexus does not operate as an openrelay server, preventing third-parties from using our servers to deliver spam.
Complete Header Inspection: MailNexus inspects all message headers to ensure that users are not spoofing the headers to push through mail.
Advanced Heuristics Engine and Content Scanning: The system looks for modified headers, repetition of certain words, and compares messages to other known spam messages for similarity. Heuristics help to block messages that may get past an RBL list, since spammers frequently change URLs.
Filtering Stringency: Users and Enterprises can set their own spam filtering stringency levels, allowing them to realize their own optimal balance between minimizing false-positives delivered to the Junk Mail folder and minimizing spam in the Inbox.
Embedded Image Suppression: MailNexus allows users to disable the display of inline messages and to suppress the display of embedded images while viewing email, effectively negating two primary methods used by spammers to identify valid email addresses.
White/Black Listing: Users and Enterprises can also create their own White “Safe” Lists and Black “Block” Lists to individually classify message senders or even entire domains as spam or “not spam.”
Sender Trending: Sender trending tracks the Spam Assassin scores for users’ regular correspondents, keeping a historical average of the sender and adjusting users’ Spam score thresholds accordingly. This feature assists in reducing false-positives.
Spam Routing: Users may choose to have messages which have been flagged as spam either delivered to their Junk Mail folder, or noted as spam in the subject line and delivered to their Inbox. This latter option is of particular value to POP3 users, who may otherwise be unaware of false positives which have been delivered to their Junk Mail folder.
Virus Protection: MailNexus uses the ClamAV server-side virus scanning system that actively scans each message before it reaches a user’s inbox, preventing hundreds of thousands of viruses from reaching MailNexus users each week. Virus patterns are retrieved and loaded automatically every hour.
Cleaning Files: If a message contains a file with a parasitic virus, or some other virus that can be removed from an otherwise useful file, the system will first attempt to clean the file.
Stripping Viruses: If a message contains a file that is a Trojan Horse virus, or some other virus that contains no valuable information, the system will strip the virus from the email, and deliver the clean email to the user with a text document attached letting the user know what events occurred.