On Thu, 2004-12-09 at 00:42, David Cary Hart wrote:
I am not at all familiar with fetchmail. During a transition period, we effected ISP mail forwarding instead. The only software associated with this our endeavor is Postfix. Here's the complete UCE section. We are virtually spam free:
strict_7bit_headers = yes
This is what I don't understand. There's 7bits and there's 8bits. What's the Freaking Difference? Anyone?
RFC 2822 specifies that Internet message headers shall consist entirely of characters within the US-ASCII character set. Quoted-printable or Base64 encodings are used to represent international characters in US-ASCII. US-ASCII characters can all be represented using 7 bits. So, if a message header contains a character that has the 8th bit set, it's violating the RFC. Some spammers use accented characters in the Subject: header message body to try to get past crude message content filters that look for words like "Viagra". Enforcing strict 7-bit headers would block such spam. However, it will also block some email from people with broken mail software that does not properly encode international characters in the message header. I know Outlook Express is broken by default in this respect, but can actually be configured to do the right thing if you delve deep into the options.
Paul.
