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Re: Need clarification in SMTP RFC 2554

2001-06-26 07:12:05

On Tue, Jun 26, 2001 at 07:05:40PM +0530, Koti wrote:
Content-Type: multipart/alternative;

  NEVER post  text/html  -- any email with HTML in it goes into
junk folder for processing if I have no better things to do...
( I use  "TEXT/HTML"  is signature characteristics of SPAM! )


In RFC 2554 - SMTP service extension for authentication, in AUTH command 
mentioned that "the client should send EHELO command after successful SASL 
negotioation which results in the negotiation of a security layer."

1. client should give EHLO if it wants extended SMTP service then server
    gives"250 - ..." as a reply after that client will give one auth
    mechanisam and conversatioin goes depending on authentication method.
    why client needs to give EHLO as first command after SASL negotiation?

   Just like with  STARTTLS,  after successfull authentication the server
   may enable extensions which are not normally available for everybody.
   Also, some extentions may get disabled when authentication is done.

2. If it supposed to give EHLO after successful SASL negotiation,
    How server differentiate whether that command is before SASL negotiatioin 
    or after negotiation?

   The server can keep state internally -- indeed it MUST keep state
   for several basic SMTP protocol details, adding this is trivial.

3. In authentication protocol exchange server chalenge, known as ready
  response is a 334 reply with the text part containing Base64 encoded string,
    Client answer consitsts Base64 encoded string.
    what this string?
    How client validate that string?

  That depends on the details of the particular authentication

4. when exactly CRAM or some other auth mechanisam should start?

  a) make (TCP) connection
  b) see 220 greeting
  c) do first EHLO greeting
  d) see capabilities reports (including AUTH)
  d2) Do STARTTLS, if capabilities show it, and do its EHLO greeting
      (continuing presuming the AUTH capability exists..)
  e) do AUTH
  f) do EHLO greeting again to see then current capabilities
  g) continue with message transmission

Thanks in advanse,
- Koteswara Rao
Ph: 040 6513274 Extn: 8842
JUNO online services Dev Pvt Ltd.
GPR building, Begumpet,
Hyderabad, India

/Matti Aarnio   <mea(_at_)nic(_dot_)funet(_dot_)fi>

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