Re: Question about smtplib, and mail servers in general.
On Wed, 21 Sep 2005 07:50:26 +0100, rumours say that Steve Holden <[EMAIL PROTECTED]> might have written: >I agree that there's an element of the moral imperative in my assertion >that the mails "should" go through which is largely ignored by the real >world nowadays. Some ISPs force you to use their SMTP servers no matter >what the sending domain, which is rather annoying when you travel a lot. >I end up having to vary my default SMTP server as I move. ...or set up your email client to always connect to localhost ports eg 31025 and 31110, and then from wherever you are, you connect to an SSH server trusted by your "standard" mail server and port-forward to it. Don't know if this applies to your case, but it works for me :) -- Christos Georgiou, Customer Support Engineer Silicon Solutions, Medicon Ltd. Melitonos 5, Gerakas 153 44 Greece Tel +30 21 06606195 Fax +30 21 06606599 Mob +30 693 6606195 "Dave always exaggerated." --HAL -- http://mail.python.org/mailman/listinfo/python-list
Re: Question about smtplib, and mail servers in general.
On Tue, 20 Sep 2005 16:48:41 +0200, rumours say that Piet van Oostrum <[EMAIL PROTECTED]> might have written: >And most smtp servers that I know also pass mail from any from-address to >any to-address if the IP number of he client machine belongs to a trusted >range (usually the range that belongs to the ISP). So I can send both my >private mail and my work mail from both my home ISP's smtp server and my >work's smtp server (but only if I am at the proper location). You might start having troubles, though, as soon as SPF checks get more widespread. Say your work mail is [EMAIL PROTECTED], and your private mail is [EMAIL PROTECTED]; if you send email through your office mail server with the envelope "MAIL FROM: [EMAIL PROTECTED]", then some (and eventually many) receiving servers shall ask yagoohoogle.com for their SPF record, and since your office mail server won't probably show up as a valid email sender from yagoohoogle.com , your email will get rejected. That's a good thing. -- TZOTZIOY, I speak England very best. "Dear Paul, please stop spamming us." The Corinthians -- http://mail.python.org/mailman/listinfo/python-list
Re: Question about smtplib, and mail servers in general.
Peter Hansen wrote: > Steve Holden wrote: > >>Peter Hansen wrote: >> >>>In any case, unless the mail server will allow "relaying", which most >>>don't these days (to prevent spamming), then it won't work the way you >>>are hoping unless *all* the 100 addresses are local ones, to be >>>delivered to users on the server you are sending the mail to. >>> >>>If the addresses are scattered all over the planet, and the server >>>allows relaying, then it's intended for exactly this sort of use >>>(other than if it's spam ;-) ), and no, you won't be putting a "drain" >>>on the server. >> >>To add one final note, if the "fromaddress" belongs to a domain that's >>properly handled by the SMTP server then you aren't relaying (since you >>are a legitimate domain user) so the mails should go through. > > > I think that statement might not be widely valid any more, Steve. In my > experience, lately, many if not most servers pay no attention to the > "MAIL FROM" address but instead allow relaying only from *IP addresses* > on the "internal" network (e.g. those served by an ISP, for example), > regardless of how the sender is identified. On a Linux box with Qmail, > for example, one would have an /etc/tcp.smtp file which specifies for > which subnets relaying is allowed, and all others are disallowed > regardless of the claimed MAIL FROM address. > > It's kind of a shame, really, that you can no longer trust either the > recipient *or* the sender addresses when using basic SMTP. Damn spammers. > I agree that there's an element of the moral imperative in my assertion that the mails "should" go through which is largely ignored by the real world nowadays. Some ISPs force you to use their SMTP servers no matter what the sending domain, which is rather annoying when you travel a lot. I end up having to vary my default SMTP server as I move. regards Steve -- Steve Holden +44 150 684 7255 +1 800 494 3119 Holden Web LLC www.holdenweb.com PyCon TX 2006 www.pycon.org -- http://mail.python.org/mailman/listinfo/python-list
Re: Question about smtplib, and mail servers in general.
Steve Holden wrote: > Peter Hansen wrote: >> In any case, unless the mail server will allow "relaying", which most >> don't these days (to prevent spamming), then it won't work the way you >> are hoping unless *all* the 100 addresses are local ones, to be >> delivered to users on the server you are sending the mail to. >> >> If the addresses are scattered all over the planet, and the server >> allows relaying, then it's intended for exactly this sort of use >> (other than if it's spam ;-) ), and no, you won't be putting a "drain" >> on the server. > > To add one final note, if the "fromaddress" belongs to a domain that's > properly handled by the SMTP server then you aren't relaying (since you > are a legitimate domain user) so the mails should go through. I think that statement might not be widely valid any more, Steve. In my experience, lately, many if not most servers pay no attention to the "MAIL FROM" address but instead allow relaying only from *IP addresses* on the "internal" network (e.g. those served by an ISP, for example), regardless of how the sender is identified. On a Linux box with Qmail, for example, one would have an /etc/tcp.smtp file which specifies for which subnets relaying is allowed, and all others are disallowed regardless of the claimed MAIL FROM address. It's kind of a shame, really, that you can no longer trust either the recipient *or* the sender addresses when using basic SMTP. Damn spammers. -Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: Question about smtplib, and mail servers in general.
Peter Hansen <[EMAIL PROTECTED]> writes:
> Daniel Dittmar wrote:
>> Chris Dewin wrote:
>>> Hi. I've been thinking about using smtplib to run a mailing list
>>> from my website.
>>>
>>> s = smtplib.SMTP("server")
>>> s.sendmail(fromaddress, toaddresess, msg)
>>>
>>> I know that in this instance, the toaddresses variable can be a variable
>>> of type list.
>>>
>>> Suppose the list contains well over 100 emails. Would that create some
>>> sort of drain on the mail server? Would I be better off doing it in some
>>> other way?
>> Not really an answer to your question, but it's probably considered
>> bad style to publish the email addresses of the recipients via the
>> address list. Use a neutral To-address (best: the mailing list
>> address) and add the recipients via bcc: headers.
>
> Not only not an answer, but also not a valid point in this case. The
> list of recipients used in the sendmail() call (which become RCPT TO:
> commands in SMTP) do *not* show up in the received emails.
Not quite. The email address each letter is actually delivered to
generally shows up in one or more Received: headers in the received
email. Some MTAs will add a header (qmail adds Delivered-To:, for
instance) with that same address in it when they deliver the mail
locally. Most MUAs don't display those, but they are there. There may
be an MTA that will pass a single message along to multiple recipients
after adding all of them to one or more headers. I don't know that
such exist - but I wouldn't trust that they don't.
Since you shouldn't trust email to be secure in any case, this isn't a
big deal. Note that using Bcc: doesn't help with this issue - the
addresses a message is delivered to *have* to be in the envelope. Bcc
puts them there and not in the headers.
http://www.mired.org/home/mwm/
Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information.
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Re: Question about smtplib, and mail servers in general.
> Steve Holden <[EMAIL PROTECTED]> (SH) wrote: >SH> To add one final note, if the "fromaddress" belongs to a domain that's >SH> properly handled by the SMTP server then you aren't relaying (since you are >SH> a legitimate domain user) so the mails should go through. And most smtp servers that I know also pass mail from any from-address to any to-address if the IP number of he client machine belongs to a trusted range (usually the range that belongs to the ISP). So I can send both my private mail and my work mail from both my home ISP's smtp server and my work's smtp server (but only if I am at the proper location). -- Piet van Oostrum <[EMAIL PROTECTED]> URL: http://www.cs.uu.nl/~piet [PGP 8DAE142BE17999C4] Private email: [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
Re: Question about smtplib, and mail servers in general.
Peter Hansen wrote:
> Chris Dewin wrote:
>
>>Hi. I've been thinking about using smtplib to run a mailing list from my
>>website.
>>
>>s = smtplib.SMTP("server")
>>s.sendmail(fromaddress, toaddresess, msg)
>>
>>I know that in this instance, the toaddresses variable can be a variable
>>of type list.
>>
>>Suppose the list contains well over 100 emails. Would that create some
>>sort of drain on the mail server? Would I be better off doing it in some
>>other way?
>
>
> Definitely consider a proper mailing list program like Mailman, as
> Daniel suggested.
>
> In any case, unless the mail server will allow "relaying", which most
> don't these days (to prevent spamming), then it won't work the way you
> are hoping unless *all* the 100 addresses are local ones, to be
> delivered to users on the server you are sending the mail to.
>
> If the addresses are scattered all over the planet, and the server
> allows relaying, then it's intended for exactly this sort of use (other
> than if it's spam ;-) ), and no, you won't be putting a "drain" on the
> server.
>
> -Peter
To add one final note, if the "fromaddress" belongs to a domain that's
properly handled by the SMTP server then you aren't relaying (since you
are a legitimate domain user) so the mails should go through.
regards
Steve
--
Steve Holden +44 150 684 7255 +1 800 494 3119
Holden Web LLC www.holdenweb.com
PyCon TX 2006 www.pycon.org
--
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Re: Question about smtplib, and mail servers in general.
Chris Dewin wrote:
> Hi. I've been thinking about using smtplib to run a mailing list from my
> website.
>
> s = smtplib.SMTP("server")
> s.sendmail(fromaddress, toaddresess, msg)
>
> I know that in this instance, the toaddresses variable can be a variable
> of type list.
>
> Suppose the list contains well over 100 emails. Would that create some
> sort of drain on the mail server? Would I be better off doing it in some
> other way?
Definitely consider a proper mailing list program like Mailman, as
Daniel suggested.
In any case, unless the mail server will allow "relaying", which most
don't these days (to prevent spamming), then it won't work the way you
are hoping unless *all* the 100 addresses are local ones, to be
delivered to users on the server you are sending the mail to.
If the addresses are scattered all over the planet, and the server
allows relaying, then it's intended for exactly this sort of use (other
than if it's spam ;-) ), and no, you won't be putting a "drain" on the
server.
-Peter
--
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Re: Question about smtplib, and mail servers in general.
Daniel Dittmar wrote:
> Chris Dewin wrote:
>
>> Hi. I've been thinking about using smtplib to run a mailing list from
>> my website.
>>
>> s = smtplib.SMTP("server")
>> s.sendmail(fromaddress, toaddresess, msg)
>>
>> I know that in this instance, the toaddresses variable can be a variable
>> of type list.
>>
>> Suppose the list contains well over 100 emails. Would that create some
>> sort of drain on the mail server? Would I be better off doing it in some
>> other way?
>
> Not really an answer to your question, but it's probably considered bad
> style to publish the email addresses of the recipients via the address
> list. Use a neutral To-address (best: the mailing list address) and add
> the recipients via bcc: headers.
Not only not an answer, but also not a valid point in this case. The
list of recipients used in the sendmail() call (which become RCPT TO:
commands in SMTP) do *not* show up in the received emails. Only those
items explicitly listed in the headers, such as the To: header, will
appear. In fact, you could easily make a Bcc: header which actually
lists everyone and it would probably not even be stripped by most mail
programs (though I haven't tried that). Your confusion is caused by not
distinguishing between mail client programs and a lower level utility
such as smtplib, which doesn't even look at the To: addresses in the header.
-Peter
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Re: Question about smtplib, and mail servers in general.
On 20/09/05, Daniel Dittmar <[EMAIL PROTECTED]> wrote:
> Chris Dewin wrote:
> > Hi. I've been thinking about using smtplib to run a mailing list from my
> > website.
> >
> > s = smtplib.SMTP("server")
> > s.sendmail(fromaddress, toaddresess, msg)
> >
>
> Not really an answer to your question, but it's probably considered bad
> style to publish the email addresses of the recipients via the address
> list. Use a neutral To-address (best: the mailing list address) and add
> the recipients via bcc: headers.
>
For clarity
The toaddreses don't show in the email, they are the envelope TO:
addreses. The addresses in the email's TO: Headers are shown to the
recipient and these are the ones that should be "disguised" as best
practice for mailing lists.
The email module's replace_header('to', 'new-text) will do the job for you.
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Re: Question about smtplib, and mail servers in general.
Chris Dewin wrote:
> Hi. I've been thinking about using smtplib to run a mailing list from my
> website.
>
> s = smtplib.SMTP("server")
> s.sendmail(fromaddress, toaddresess, msg)
>
> I know that in this instance, the toaddresses variable can be a variable
> of type list.
>
> Suppose the list contains well over 100 emails. Would that create some
> sort of drain on the mail server? Would I be better off doing it in some
> other way?
>
Not really an answer to your question, but it's probably considered bad
style to publish the email addresses of the recipients via the address
list. Use a neutral To-address (best: the mailing list address) and add
the recipients via bcc: headers.
You might also want to look at mailman
http://www.gnu.org/software/mailman/, which is a complete mailing list
solution written in Python.
Daniel
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Re: Question about smtplib, and mail servers in general.
On 20/09/05, Chris Dewin <[EMAIL PROTECTED]> wrote:
>
> s = smtplib.SMTP("server")
> s.sendmail(fromaddress, toaddresess, msg)
>
> I know that in this instance, the toaddresses variable can be a variable
> of type list.
>
> Suppose the list contains well over 100 emails. Would that create some
> sort of drain on the mail server? Would I be better off doing it in some
> other way?
> Suppose the list contains well over 100 emails
You mean the list of recipients (toaddresses) ?
The 2 lines of example code send a *single* email to "server" with
len(toaddresses) recipients. The server will then split the email
into smaller (or individual) email groups to send (depending on the
server in use and the mechanisms it uses to relay the email)
You could send a single email for each recipient to "server"
> s = smtplib.SMTP("server")
>for addr in toaddresses:
> s.sendmail(fromaddress,[addr], msg)
# in later revisions, [addr] can be a list, or a string of one address
but that would create much more load on your machine AND server
HTH :)
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