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Unformatted text preview: starts to send it. This command was added since the size of Internet mail
messages is growing, with the support for message content other than ASCII lines (i.e.,
images, audio, etc.).
The next host also supports ESMTP. Notice that the 250 reply specifying that the SIZE
keyword is supported contains an optional argument. This indicates that this server will
accept a message size up to 461 Mbytes.
sun % telnet ymir.claremont.edu 25
220 ymir.claremont.edu -- Server SMTP (PMDF V4.2-13 #4220)
250-ymir.claremont.edu file:///D|/Documents%20and%20Settings/bigini/Doc...omenet2run/tcpip/tcp-ip-illustrated/smtp_sim.htm (15 of 23) [12/09/2001 14.47.52] Chapter 28. SMTP: Simple Mail Transfer Protocol 250-8BITMIME
250 SIZE 461544960
The keyword 8BITMIME is from RFC 1426 [Klensin et al. 1993b]. This allows the client
to add the keyword BODY to the MAIL FROM command, specifying whether the body
contains NVT ASCII characters (the default) or 8-bit data. Unless the client receives the
8BITMIME keyword from the server in response to a EHLO command, the client is
forbidden from sending any characters other than NVT ASCII. (When we talk about
MIME in this section, we'll see that an 8-bit SMTP transport is not required by MIME.)
This server also advertises the XADR keyword. Any keyword that begins with an X refers
to a local SMTP extension.
The next server also supports ESMTP, advertising the HELP and SIZE keywords that
we've already seen. It also supports three local extensions that begin with an X.
sun % telnet dbc.mtview.ca.us 25
220 dbc.mtview.ca.us Sendmail 5.65/3.1.090690, it's Mon, 2
Aug 93 15:48:50 -0700
ehlo sun. tuc.noao.edu
250-Hello sun.tuc.noao.edu, pleased to meet you
Finally we see what happens when the client tries to use ESMTP by issuing the EHLO
command to a server that doesn't support it.
sun % telnet relay1.uu.net 25
220 relay1.UU.NET Sendmail 5.61/UUNET-internet-primary ready
at Mon, 2 Aug 9...
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This test prep was uploaded on 04/04/2014 for the course ECE EL5373 taught by Professor Guoyang during the Spring '12 term at NYU Poly.
- Spring '12