Some things still wonder me,after 10+ years of web-development. Todays wonder is here:
RFC2821 (SMTP) tells:The maximum total length of a text line including the <CRLF>is 1000 characters
. In real world,most MTAs default to 990 characters per-line,which means,that if you will try to dump longer line on them,they would split it by putting “!\n”after 990-th byte. This is mostly harmless for plain-text,but can easily break html.
Actually,there is even a PHP-bug reported,regarding this,but PHP obviously can’t do anything to help the situation
The solution is really simple:if there is a chance,that lines of your emails would be longer than 990 bytes encode body using base-64. The easiest way to do it for emails without attachments,in php is to use mb_send_mail() function instead of mail(),as it will apply encoding automatically.
