2 ms·

I got the 35MB by connecting to their MX and then looking at the value returned by the SIZE ESMTP extension: mike@alfa:~$ telnet gmail-smtp-in.l.google.com 2

I got the 35MB by connecting to their MX and then looking at the value returned by the SIZE ESMTP extension: mike@alfa:~$ telnet gmail-smtp-in.l.google.com 25 Trying 209.85.143.27... Connected to gmail-smtp-in.l.google.com. Escape character is '^]'. 220 mx.google.com ESMTP z4si16632304weq.140 EHLO mail.cardwellit.com 250-mx.google.com at your service, [178.79.145.246] 250-SIZE 35882577 250-8BITMIME 250-STARTTLS 250 ENHANCEDSTATUSCODES Their MX states that it accepts messages up to 35882577 bytes in size, which is just under 35MB.

ianterrell 15y ago
That's a great bit of technical expectation management. "We'll accept up to 25MB!" And then when you send something 26 or 27MB because you don't notice that it's so close to the limit, the system forgives you.
- gvb 15y ago
  More likely it is an accommodation of base64[1] (MIME) encoding of binary files, which results in a 30% expansion (3 bytes get encoded to 4): 25MB * (4/3) = 33MB. People who read that GMail is limited to 25MB will expect their 25MB photo to be accepted. This requires the absolute size limit to be set to 33MB (probably bumped up to 35MB to accommodate the HTML body and other spurious stuff like the 25 off-topic replies). [1] http://en.wikipedia.org/wiki/Base64 http://en.wikipedia.org/wiki/Base64