Network Box POP3 Acceleration

NETWORK BOX NBRS-3 TECHNICAL WHITE PAPER

Network Box POP3 Acceleration
Background
POP3 is an Internet standard protocol used to retrieve email from a remote server over a TCP/IP connection. Subscribers to individual ISP (Internet Service Provider) email accounts usually access their email with client software that uses POP3. Smaller organizations often outsource their email server to their ISP and use POP3 to access their email for multiple accounts on a domain CONTENT hosted on the ISP's email servers.
The design of POP3 and its procedures support end-users with intermittent Background...........................................1 connections to retrieve email when connected and then to view and manipulate the retrieved messages without needing to stay connected. Although most clients Acceleration.........................................2 have an option to leave mail on server, email clients using POP3 generally connect, retrieve all messages, store them on the client workstation as new Server Groups and Accelerated messages, delete them from the server, and then disconnect.Accounts...............................................3
POP3 typically operates over the tcp/ip protocol on port 110, with the client Authentication Changes....................3 making a connection to the server. Given an interception ability (such as typically available on a gateway device), it is possible to intercept the protocol "Leave on Server" Facility.................4 and provide transparent scanning of messages to enforce anti-virus, anti-spam and policy regulations. However, there are two primary limitations imposed by Laptops in and out of the Of?ce.....4 the protocol in such an interception mode:Conclusion...........................................4 1. The RETR command (used to retrieve a message from the server) does not support a clean reject/drop indication. If a violation is DECEMBER 2007No part of this publication including text, examples, detected during anti-virus/anti-spam/policy enforcement, there is no or illustrations may be reproduced, transmitted, clean way to inform the client the message is not available (without or translated in any form or by any means, aborting the entire transfer and displaying an error message on the electronic, mechanical, manual, optical or otherwise, client workstation).for any purpose, without prior written permission of Network Box Corporation Limited. 2. The anti-virus/anti-spam/policy scan will inevitably slow down the Network Box Corporation Limited, retrieval of messages from the server. This will usually be apparent 16th Floor, Metro Loft, to the user.38 Kwai Hei Street, Kwai Chung,Kowloon, Hong KongTelephone: +852 2736-2083 The practical impact of these limitations is that the POP3 protocol, in standard Fax: +852 2736-2778 intercept mode, can only be used to 'filter' messages, has no quarantine ability, www.network-box.com and will visual impact the performance of email retrieval at the client workstation.
The Network Box POP3 Acceleration system avoids both these limitations, while still operating in a transparent intercept mode with no required re-configuration of the mail client.
1 NETWORK BOX CORPORATION LIMITED, 16TH FLOOR METRO LOFT, 38 KWAI HEI STREET. KWAI CHUNG, KOWLOON, HONG KONG TELEPHONE: +852 2736-2083 FAX: +852 2736-2778NETWORK BOX NBRS-3 TECHNICAL WHITE PAPER

Acceleration
The basic mechanism behind Network Box POP3 Acceleration is to completely separate the client-server communications channel to two new channels client->Network-Box and Network-Box->Server.
By monitoring the client->server communications protocol during an intercepted POP3 connection, the Network Box POP3 proxy transparently learns the client authentication credentials and server parameters. If configured to accelerate that connection (based on the server and pop3 user account) the Network Box takes over the client connection, disconnects the server connection (separating the client from the server) and acts as a POP3 server itself to the client.
POP3 'Spider' services running on the Network Box periodically poll POP3 accelerated accounts. They connect to the server, ... [download for more]