ReSieve Help File 

Proxy Chaining

Introduction

ReSieve is an email proxy. In the simplest possible installation, ReSieve is an intermediary that passes along communications between your email client (e.g. Outlook) and your email server (e.g. pop.your_isp.com).

 

Simple ReSieve installation
	Email client	→	ReSieve	→	Email server
IP address	talks to	IP-of-your-device	talks to	mail.isp.net
POP port	over port	110	over port	110

A mail client sends a request through ReSieve, and ReSieve to the mail server for email. The mail server responds by sending the email to ReSieve which tags the email with categories or buckets and delivers them immediately to the mail client.

If you are using any additional email proxies with ReSieve such as certain antivirus software, YahooPOPs, or Hotpopper, you need to configure them to work together in a daisy chained fashion like so:

 

Configuring ReSieve to work with another proxy
	Email client	→	ReSieve	(antivirus, etc.)	→	Email server
IP address	talks to	ReSieve	talks to	talks to	mail.isp.net
POP port	over port	123	over port	over port	110

This allows a virus checker to check email for viruses before they reach ReSieve or your mail client or for Yahoo Pops to fetch mail from a Yahoo account. Note that you want to avoid conflicts with other proxies by either a) using different ports or b) a different IP address. However, a different IP address is often not practical for this particular application because your proxies (e.g. virus checker and spam checker) are running together on your local machine. If none of that makes sense, that's okay it isn't essential to using ReSieve. Keep reading on.

The port you set in ReSieve, the POP3 listen port setting on configuration button and in your email client (the pop or incoming server) are different than the setting your mail server uses (110 by convention) and the other proxy.

Instructions

The instructions below assume you have a mail proxy installed that inserts itself as a proxy like ReSieve does. If you plan to install both an antivirus program and ReSieve but have installed neither yet, install the antivirus software first according to the instructions provided by the author(s) of the software and then verify that you can a) get email and b) the antivirus software is working correctly. Then install ReSieve following the directions below.

The most common example is probably an antivirus program. Some proxies act transparently, so the instructions will vary. See Norton Antivirus.

• Note that before installing ReSieve, the mail client contains the following entries made by the virus scanner:

  pop3 server: 127.0.0.1
  username: pop.isp.net:user

  • where pop.isp.net is your mail server, user is your login name, and 127.0.0.1 indicates the "localhost" or computer that you are running your email client and virus software on.
  • Although not stated explicitly, the above implies that the virus scanner listens on port 110. Generally the port for the mail server is specified elsewhere in your mail client, but 110 is the most common setting.
    
• Using configuration button, set the ReSieve listen port to 123 and the POP3 host:port:user separator character: to a percent sign %.
• Change the mail client's setup as follows:

  pop3 server: 127.0.0.1
  pop3 port: 123
  username: 127.0.0.1:124%pop.isp.net:110:user
  

• The above setup tells the mail client to contact ReSieve on IP address 127.0.0.1 and port 123 (instead of the antivirus software as the email client did originally).
• ReSieve will examine the username and strip off the left side of the username (where the % is the division point), and use that to contact the virus scanner on 127.0.0.1 port 124, and pass the right side to the virus scanner as the username.
• The virus scanner, listening on port 124, gets the username and strips it's left side off (remember it uses : as its separator), getting the address pop.isp.net to contact the real mail server on port 110, using the right side username of user.

So the general format for using two chained proxies, ReSieve, and a mail client is:

proxy[:port]%pop.mailserver.net[:port]:username

where:

• The text inside "[ ]" is optional depending on the situation.
• The % as a center line; everything to the left of the percent sign is the left side; everything to the right is the right side.
• The left-side entry should be the first proxy in the chain relative to the mail client.
• The chain should end at the real mail server.
• The left side needs to be formatted for ReSieve while the right side needs to conform to whatever that next proxy wants to see.
• Note that the colon followed by port number is unaffected by whatever the pop3_separator character is set to be.