W B Hacker wrote:
> Phil Pennock wrote:
>
>> On 2008-01-13 at 15:40 -0800, chuckee wrote:
>>
>>> I want to have Exim open on port 80 on my server (say, myserver.com),
>>> however I also have a website that needs to be visible (on port 80), at
>>> least on www.myserver.com and also myserver.com if possible.
>>>
>> Quite aside from the policy and other issues raised, technically you
>> can't reliably do this.
>>
>> In HTTP the client sends first and an SMTP banner would be quite bad
>> unexpected data. In SMTP, the server sends first, sending a banner, so
>> the client waits until it sees something from the server.
>>
>> If SMTP clients sent first then you might have been able to do a clever
>> protocol analysis hack in the web-server to pass things off to Exim, but
>> they don't and so you can't
>
> Though I agree (from actual testing) that use of port 80 is a bad idea,
> for smtp - the above does not apply in practice.
>
> The MTA and the MUA both still 'know' they are using smtp protocol,
> (indeed - have scant choice...) so whatever an httpd or browser would do
> is not relevant to getting a working session established on whatever
> choice of ports one chooses. It is not even a strict requirement that
> one edits /etc/services UNLESS relying on inetd.
>
> Not with Exim as MTA and either Mozilla suite or SeaMonkey suite or
> Opera suite as MUA anyway - and all three of those are also browsers,
> but 'confusethed not' the relevant protocols (did make cert installation
> easier, though).
>
>
I think Phil's message was refering to the "I also have a website that
needs to be visible (on port 80), [on] myserver.com if possible" part of
the original message.
What he means is that if SMTP and HTTP both had the client "talk" first
then a program could be setup on the server to accept a connection,
analyse the incoming data and then forward it to either the web or mail
server.
Since an SMTP client won't send anything until it sees the banner, there
is no reliable way to tell the difference between an SMTP connection and
a slow HTTP connection (and sending the SMTP banner would mess things up
if it was an HTTP connection).
*Michael Heydon - IT Administrator *
michaelh@??? <
mailto:michaelh@jaswin.com.au>
