Microsoft’s Enforcing of SPF is Good

Some commentators have reacted badly to the recent announcement that MSN will start testing for the presence of senders’ SPF records. They have described it as "Microsoft pushing Sender ID down peoples’ throats."  We disagree

Microsoft isn’t asking people to publish SPFv2 records, just SPFv1. Neither is it making them add Sender ID-specific headers to their messages. It’s simply looking for the presence of an SPF record for the sender’s domain, and adding that information into the mix of their anti-spam rules and heuristics.

Also, there’s no requirement on any other email receiving servers to filter using Sender ID’s PRA (purported responsible address) algorithm. Using the Sender ID algorithms to filter spam, as opposed to the SPF algorithms, is entirely in Microsoft’s purview. "My server; my rules," as the saying goes.

The proposed new spam filtering rule at MSN means that certain messages are more likely to be filtered as spam, and certain other messages are less likely to be filtered. This will encourage domain owners to publish SPF records. This is a good thing. Microsoft is using its position as a very large email provider for good.

Author: Richi Jennings, with thanks to Curt Monash for the idea

One Comment

  1. Posted June 30, 2005 at 10:40 AM | Permalink

    Certainly, some observers have exaggerated Microsoft’s plans and their intentions. But people would do well to be wary any time Microsoft seems to be using their scale to force change.

    Also of concern is the fact that this unilateral step may violate Postel’s Robustness Principle (“be conservative in what you send, liberal in what you accept”), the cornerstone of getting multiple implementations of open standards to interoperate. This can lead to less interoperability of the Internet email. If that is the result, then by any definition, it will have been a bad thing.

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