Singaravel.M (nymshifter of "message size limit", his post again
rephrased said:
The same file with 700 KB size can be forwarded using OWA to the same
recipient, but not in Outlook.
For OWA, you are using a web browser. OWA is the connector at the
Exchange server. Because you are using a web browser, the only way to
get the attached file to the mail server is via the same HTTP protocol
you are using to connect to the OWA service. The size of the
transmitted file does not change (on your end).
When you use a local e-mail client, EVERYTHING gets sent as text.
Whether you send in plain-text, HTML, or RTF format, the entire content
of the e-mail is text. Coding is used along with content headers for
HTML and RTF formatted e-mails, like using <tags> in the text of a
message for the HTML coding. Attachments are not somehow attached to an
e-mail or float along with it. They are *in* the body of the e-mail as
a MIME part. This encodes the file into a long text string. This
encoding will increase the size of the file by 37% when it gets
converted into the text string inside the MIME part in the body of your
raw message.
When sending e-mail, often just plain-text suffices to convey your
message. Using HTML will double the size of your e-mail (excluding the
attachments since they are separate MIME sections). One copy of your
message will be in plain-text so those that cannot read HTML-formatted
e-mails or a recipient may configure their e-mail client to use only
plain-text format for reading e-mails. By having the plain-text version
in your message, you ensure those recipients can still read your
message. Another copy of your message gets put into your e-mail for the
HTML-formatted version. So your HTML-formatted e-mail has two versions
of your message within it: a plain-text version and an HTML version.
That doubles the size of the body of your e-mail. The attachments don't
get doubled because they are delimited by separate MIME sections.
So how large is your e-mail depends on whether you send in plain-text or
HTML format along with including any attachments (which will mushroom in
size by an additional 37% when converted into long text strings so they
can go into your e-mail). All e-mail goes as text. HTML is text.
Attachments are text (after conversion).
If you were to send a 15KB message in HTML format, the body will be a
bit over 30KB in size: 15KB for the text version, 15KB for the HTML
version, and some overhead for the HTML tags in the HTML version. Your
700KB attached file would bloat to 959 KB at a minimum (the 37% is an
expected or average value). Your total message would be 989 MB. That
is the binary value (where 1 MB or 1 MiB = 2^20 bytes) whereas some mail
servers will use decimal values in their quotas, so 989 KiB becomes 1037
KB in decimal; see
http://en.wikipedia.org/wiki/Mebibyte. If your max
message size quota is 1 MB (in decimal), your message with its
duplicated HTML version and the converted attachment after its bloat
exceeded your quota. 1 MB does seem a bit low but then perhaps it is
your employer that operates the POP server and expects you to do only
company e-mails when using company property and that large attachments
are supposed to get put on a networked file server, in Sharepoint, or
some other shareable resource. Typical e-mails (just their text) are
under 15 KB in size (and often run under 5 KB). HTML doubles that size
but isn't a problem *if* only considering the text of the message. Once
you start attaching files to your message, you could easily exceed their
quotas. For company e-mails, they may expect you to place large files
on a shared resource and link to them in your e-mail.
With OWA, the files isn't attached but sent via HTTP. That means the
company's mail server receives it unbloated. However, to put it into
your e-mail before it gets sent means it will have to still get
converted from binary to text and that will bloat the size of your
message (unless Exchange via OWA somehow differently handles attachments
but which would only be where sender and recipient are BOTH on the same
Exchange server). If your e-mail got sent out from your company, it
would have to behave as an SMTP mail server which means the file must
get converted into text within a MIME part in your message before
getting delivered outside the company. I don't know how Exchange
handles attachments for internal-only e-mails.
To see how large will be your e-mail sent as it will be sent from a
local e-mail client, save a draft of it. Then go into the Drafts folder
and look in the Size column. You will have to discuss with whomever
operates the POP mail server as to what are their quotas, like maximum
message size, for the type of e-mail account that you have with them.
