Re: [SLUG] Email Domains --- handling of invalid email addresses
Peter Chubb wrote: As a general rule bounces are evil. I'm planning to give a talk at SLUG on this next month, if the committee agree The major exception to that would be messages submitted down the Submission (STMP+TLS+AUTH) port. You know they aren't spam or relayed, so full service can be given. -- Glen Turner -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
[SLUG] Email Domains --- handling of invalid email addresses
Thankyou all for the feedback. I think I see what the problem is now. Some ISPs simply seem to think that: - all BOUNCE messages are unsolicited & _therefore_ ALL unsolicited messages are SPAM ! Is this absolutely True!! of course not! If I misspell a username I WANT a bounce message to ALERT me to the fact. ( especially if the same MTA is sender & receiver) Now some people will not appreciated some bounces are solicited and some are UNsolicited. A bounce from a spoofed sender address would be an unsolicited message and herein lies the problem! Some ISPs seem to try to differentiate and some won't even bother. Special cases of eating email when identified as -spam - or with viruses - or with invalid sender address . seems reasonable to me though. It seems that enforcing RFC's would be impossible given everyones feedback. All this still does beg the Question Does not bouncing reduce spam? If postmaster AT firstMTAdomain.xxx sends all the bounces , email loops would not exist ... I would suggest. That is a question I will pose to exetel. Thx again Roger -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Email Domains --- handling of invalid email addresses
Peter Chubb wrote: > I'm planning to give a talk at > SLUG on this next month, if the committee agree I'm not on the committee, but if I was, I'd be voting +1 on this :-). Cheers, Erik -- - Erik de Castro Lopo - "Every method you use to prevent or find bugs leaves a residue of subtler bugs against which those methods are ineffectual." -- Bruce Beizer's Pesticide Paradox -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Email Domains --- handling of invalid email addresses
> "R" == R G Salisbury writes: R> Some ISP's (exetel ... [EMAIL PROTECTED]) is one, that do R> not bounce notices when you send to an invalid email address). R> Some ISP's do bounce a message , so you know the status , so you R> know it is futile to try again to the same address. The best thing to do is to refuse to accept a message for an invalid user at SMTP conversation time. That way the sending MX gets to notice the problem, and generate a bounce iff appropriate. As a general rule bounces are evil. I'm planning to give a talk at SLUG on this next month, if the committee agree -- Dr Peter Chubb http://www.gelato.unsw.edu.au peterc AT gelato.unsw.edu.au http://www.ertos.nicta.com.au ERTOS within National ICT Australia -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Email Domains --- handling of invalid email addresses
On Wed, Aug 13, 2008, R.G.Salisbury wrote: > Do the RFCs suggest a recommended policy? RFC 2821: Simple Mail Transfer Protocol It includes the following: "... a formal handoff of responsibility for the message occurs: the protocol requires that a server accept responsibility for either delivering a message or properly reporting the failure to do so." "If an SMTP server has accepted the task of relaying the mail and later finds that the destination is incorrect or that the mail cannot be delivered for some other reason, then it MUST construct an "undeliverable mail" notification message and send it to the originator of the undeliverable mail (as indicated by the reverse- path). Formats specified for non-delivery reports by other standards (see, for example, [24, 25]) SHOULD be used if possible." That said, many mail server administrators accept and eat viruses and sometimes spam without ever sending an error. (Spam may or may not be stored somewhere where the addressee can optionally retrieve it, viruses not so much.) It's far less common to accept and eat mail to entirely non-valid addresses. The standard practice as far as I know is to reject them immediately whereever possible (ie not to accept them, go check with the list of valid users, and then generate a bounce and send it out separately). -Mary -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
Re: [SLUG] Email Domains --- handling of invalid email addresses
On Wed, 2008-08-13 at 13:29 +1000, R.G.Salisbury wrote: > Some ISP's do bounce a message , so you know the status , so you know it is > futile to try again to the same address. Knowing the dictionary attacks that spammers do and how often I get thousands (litterally) of bounced emails that they send out using my email address, I vote for no response. If the email server spec allows you to tell when the mail is sent that is different, just that bounced reply is a very bad idea. Ken -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
[SLUG] Email Domains --- handling of invalid email addresses
Hi all Some ISP's (exetel ... [EMAIL PROTECTED])is one, that do not bounce notices when you send to an invalid email address). Some ISP's do bounce a message , so you know the status , so you know it is futile to try again to the same address. Why ISP exetel doesn't bounce messages supposedly is to reduce spam & email loops. I am not convinced about that argument.Eg why has "greylisting" been developed? Is there a consensus as of what is normal practise? Is there an industry recommendation or policy? Do the RFCs suggest a recommended policy? Anybody with any thoughts on This? Thanks in advanced Much appreciated ! Roger Salisbury -- SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/ Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
