Sender Rewriting Scheme - SRS - Yaritz Consulting: The Consultation Company  

SRS (Sender Rewriting Scheme)

SRS is a solution that will allow UCE (Unsolicited Commercial Email, formerly known as spam) to be blocked using real UCE blocking methods.  SRS does not directly block UCE.  Previously, email was routed through costly internet links, through a server called the relay.  This server allowed anyone to send email through it.  Most relay servers now require authentication to relay.  Email also allows for masquerading.  Masquerading is the sending of E-Mail as someone else.  This is required because people want to forward their E-Mail from one account to another.  Forwarding E-Mail is simply done by masquerading.  The problem with masquerading is that when you allow someone else to send E-Mail as you, malicious people also like to use this exploit.

RBLs were an attempt to stop this and worked rather quite nicely, until UCE offenders across the internet started IP hopping.  IP hopping is where they get on one IP and send a little and then another IP and a send little more.  IP hopping is annoying once you realize that you just picked up an IP that was previously used in IP hopping.  SRS brings back the RBL like blocking by allowing the blocking methods of SPF and grey listing.  SRS is an attempt to allow legitimate people to forward E-Mail in a safe manner.  It works by rewriting the envelope address to come from your server.  SRS also can also send a message back to the originator in such a manner that they will not know that it is a forwarding address.

SRS is enabled by installing the add-on onto your server (Provided you are forwarding.):

  1. Install an SRS package of your choice.
  2. Now enable this package on your server.
  3. Test your installation

NOTE: Please be aware that SRS is not a solution unless you prevent UCE from coming into your server.  Remember that SRS only allows other UCE prevention tools to exists.  By installing SPF and Grey listing on your server, the relay of UCE will be minimzed, effectively saving you heartache and time.

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