Corruption by added dots
I added the section on corruption of email by added dots. This does happen, and is not a one-off occurrence, although hopefully rare.
I have the misfortune of being involvbed with a database which sends out updates via email, using Outlook Express (OE) as MAPI client. After an outbreak of corruption, I find that OE uses quoted-printable (qp) encoding for files which are predominantly ASCII text; this cannot be overriden. When email was sent to users of a particular ISP, a dot was prefixed to every line beginning with the dot. If it just so happened that the database file being sent had a line beginning with a dot, it became corrupted.
This was not a unique problem; there were 4 outbreaks of intermittent corruption on 3 different ISPs. These were simply ISPs we used; this is not the result of a check on a wide selection of ISPs. In two cases the ISP confirmed that there had been an error in software at their end.
Binary encoding protocols don't use the dot character, to avoid just this sort of problem.
I won't go into details, but thsi has to do with the Internet mail system adding temporary dots at one end which are supposed to be stripped off ath the other.
Pol098 17:08, 24 February 2006 (UTC)
A paper clip image is the standard image for an attachment in an email client.
Services like  eParcel/Attachment-service moves attachments away from email-related systems and timestamp each eParcel to destroy the physical file after downloads. By this method mailbox size and email attachment limits can be circulated for sender and receiver.
To me, the eParcel reference sounds like a big advertisement. See https://en.wikipedia.org/wiki/Wikipedia:Spam#Affiliate_links — Preceding unsigned comment added by LeCrayonVert (talk • contribs) 22:27, 6 November 2013 (UTC)
- This looks suspiciously like advertisement. I think a number of alternatives should be mentioned, including Gmail's option to share it via Google Drive, where the recipient gets the option to obtain the file from Drive. I'm rather wary of many attachment links having noticed many virus or phishing attempts spoofing Evernote or MMS sending services. In practice, genuine, non malicious usage of web-based alternatives to attachments seems to be a very small proportion of total attachments or equivalents and a number of non technical users have difficulty when I use Google Drive to share larger files. 188.8.131.52 (talk) 11:15, 24 June 2014 (UTC)
False-positive attachment blocking - dots in filenames look like multiple extensions
I work in a company where many people put a date in a filename on Windows using dots in a format like "Scanned letter from John Doe 10.12.13.pdf" which is allowed by the OS. If these are attached to emails, many servers assume it's a multiple-extension virus attachment, like HappyNewYear.JPG.EXE, even though the true extension PDF is considered safe, and they reject the email, sometimes with a bounce, sometimes without a bounce, but with usually no explanation as to what rule caused its rejection. This is frustrating for users and although email software ought to suggest replacing dots with underscores or similar it usually doesn't, so it would be helpful to explain what might have caused their problems.
Does anyone have a Reliable Source to cite for this phenomenon - especially that it can be a false positive? We could add a False Positive or Rejected Attachment section where we detail typical reasons that attachments get rejected. Wikipedia is often people's first-stop when searching and we could provide a service to the public by paraphrasing and referencing sources of good information, but we must not contribute original research and thus cause Wikimedia Foundation to be liable for consequential damages if the information is.
Certainly, a brief list of commonly-rejected file types could be included (and references are easy to find), including extensions denoting executable or macro-containing files. A brief list of common tactics for malware and would also be helpful (e.g. Invoice.zip and links to files purporting to be from a reputable company using a similar-looking domain like invoices-amazon.com for example or linking text that looks like a legitimate URL to a download link that is not legitimate.) Dynamicimanyd (talk) 09:54, 3 July 2014 (UTC)