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Re: Last Call: 'Email Submission Between Independent Networks' to BCP - Clarification

2005-06-16 22:51:06
Because I have already recieved several comments relating to one aspect of 
my original post I thought a clarification was in order as I didn't explain 
myself properly and there is some misunderstanding.

When I wrote that "nobody would be complaining if spam primarily consisted 
of Bloomingdale's catalogues and coupon val-paks" I didn't mean we wouldn't 
complain if we recieved the same amount of spam but it was from legitimate 
companies.  I meant that maybe 1% of my spam comes from legitimate companies 
so if we got rid of the frauds we would have effectively reduced spam by 99% 
(by no means is that percentage anything more than a rough approximate 
estimate).

Best regards,

Nick Staff


Original post:


I'm sure many will think this a stupid comment, but in the hopes that some 
don't I'll point out that the largest and arguably most efficient messaging 
system in the world is built upon open relay.  Anyone can anonymously drop a 
letter in any mailbox in the US and while there's junk mail it's proportions 
are certainly nothing like spam.  Why the difference?  Well first I split 
spam into 2 categories:

1.  legitimate advertisements for legitimate products (whether solicited or 
unsolicited).
2.  Fraudulent mail, scams, cons, etc.

I think the email abusers almost entirely fall into the second category and 
that nobody would be complaining if spam primarily consisted of 
Bloomingdale's catalogues and coupon val-paks.

So I think we are attacking things the wrong way.  The methods we are 
using - whether blacklists or 'authorized email' is going to either prove 
fruitless or end up ruining the big picture, which for me is electronic 
communication for everyone, to everyone.  Using electronic means, I don't 
see how we can ever prevent spam and still have open global communication 
among disparate systems.  It would be a different story if one organization 
ran all email servers worldwide but that horrible thought aside there will 
always be holes and breaks in an authentication/authorization scheme unless 
people limit who they can communicate with, and even then there will be 
spam.

There's also the returns we see on our efforts to consider.  Think of the 
millions of man/woman hours spent trying to stop spam - so many hours it 
probably would have taken less to inspect every email by hand.  And then 
when you think (if you believe as I do) that everything can be gotten around 
and that security holes are as infinite as the imagination, well then you 
know there will always be some kid with a script (which also includes any 
real spammer) who will be able to get around your defenses within a week of 
them being implemented.

My last unconstructive comment is that simple systems scale lossless and 
complex systems grow in a complexity proportionate to their size.

Funny enough, I think the postal inspector's department came about because 
of the amount of scams being sent via mail shortly after the civil war (such 
a glut that it was bringing the postal service to their knees).  Yet the 
postal service remained open-relay - why?  Maybe because they realized that 
they didn't need to 'trace' scam-mail because scams are trace-inclusive as 
the scammer must include a point of contact.  Sure there's the occasional 
anonymous letter bomb but since their resources aren't spent blocking coupon 
mailers they are much more likely to catch the big stuff.

I know there are 8 trillion problems with this idea but I think in general, 
email fraud needs to become like mail fraud and there needs to be a team of 
inspectors who follow up on such reports and arrest violators (I know the 
Internet is bigger than the US, so of course it's up to each country how to 
handle it).  I'm sorry for the non-technical post but I think blacklists are 
disgusting (I don't care if they help or not) and I just think so much 
brilliance could be directed elsewhere.

Thanks and best regards,

Nick Staff
nick(_dot_)staff(_at_)comcast(_dot_)net

-------------- Original message -------------- 
 it's possible to have open relays that don't contribute to spam.  but
 those relays need to employ some other means, e.g. rate limiting, to

Rate limiting is a relatively recent technique.  Though very useful it 
has...
ummm, limited applicability.

mostly because of blacklists.  it was working fine for its intended purpose.

One needs to be careful not to dismiss established techniques in favor of 
the
latest fashionable one that is not as well fully understood.

I don't know what you mean by "relatively recent", but I was doing it at 
least
as early as April 1999 - that's the last mod date on my source files.  RFC 
2554
only dates from March 1999.

For example, rate limiting is used to control a single source. It's quite
useful
when used at the destination. At a sufficiently well-run source network, 
it
also
can be pretty useful.

It's also pretty useful for preventing a relay from being exploited by 
spammers.

The problem is with zombies.  They make mush of old-time models of spam, 
since
they demonstrate that a very small data stream from a single source can be
leveraged into a very, very large data stream, given enough sources.

Rate limiting of this type (based on source IP address), if done properly,
doesn't
help or hurt zombies.  The rates need to be set such that zombies can send
directly
to the recipients' MXes as easily, and more reliably, as they can send the 
same
mail via the rate limiting SMTP servers.

One can start imagining more complex rate-limiting models, but then we 
would
be
talking about research efforts.  A BCP is not supposed to rely on 
research,
especially when it hasn't been done.

Maybe you should stick to talking about things that you know something 
about.

 block spam.  the goal of such relays is to make it at least as easy for
 the spammer to simply contact the appropriate MXes for the destination
 addresses as to use the relays.  of course it is necessary for such
 relays to record source IP addresses, etc., so that they are as
 traceable to their origin as messages sent directly to MXes.

I don't know how much experience you have trying to do such tracing, but 
the
spamops folks have made quite clear that it is both vastly more effort and
considerably less productive, than one might expect.

That's a problem with mail relaying in general, not just with open relays.
Now if you want to discourage multi-hop mail relaying, that might actually 
be
useful for lots of reasons besides just traceability.

 unfortunately, the vigilante character of various open-relay blacklists

blacklists are not the subject of this BCP.

This thread has pretty much diverged from the subject of your draft
document anyway.

 killed any attempt at this kind of innovation.  just as we're now in
 danger of various kinds of brain-dead "authentication" methods and
 meaningless requirements killing useful email functionality.

new authentication methods are not the subject of this BCP.

You mean "your draft document".  It's certainly not a BCP as it's
currently written.

Keith

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--
Best regards,

Nick Staff

-------------- Original message -------------- 

it's possible to have open relays that don't contribute to spam. but
those relays need to employ some other means, e.g. rate limiting, to

Rate limiting is a relatively recent technique. Though very useful it 
has...
ummm, limited applicability.

mostly because of blacklists. it was working fine for its intended 
purpose.

One needs to be careful not to dismiss established techniques in favor 
of the
latest fashionable one that is not as well fully understood.

I don't know what you mean by "relatively recent", but I was doing it at 
least
as early as April 1999 - that's the last mod date on my source files. RFC 
2554
only dates from March 1999.

For example! , rate limiting is used to control a single source. It's 
quite
useful
when used at the destination. At a sufficiently well-run source network, 
it
also
can be pretty useful.

It's also pretty useful for preventing a relay from being exploited by 
spammers.

The problem is with zombies. They make mush of old-time models of spam, 
since
they demonstrate that a very small data stream from a single source can 
be
leveraged into a very, very large data stream, given enough sources.

Rate limiting of this type (based on source IP address), if done properly,
doesn't
help or hurt zombies. The rates need to be set such that zombies can send
directly
to the recipients' MXes as easily, and more reliably, as they can send the 
same
mail via the rate limiting SMTP servers.

One can start imagining ! more complex rate-limiting models, but then we 
would
be
& gt; > talking about research efforts. A BCP is not supposed to rely on 
research,
especially when it hasn't been done.

Maybe you should stick to talking about things that you know something 
about.

block spam. the goal of such relays is to make it at least as easy for
the spammer to simply contact the appropriate MXes for the destination
addresses as to use the relays. of course it is necessary for such
relays to record source IP addresses, etc., so that they are as
traceable to their origin as messages sent directly to MXes.

I don't know how much experience you have trying to do such tracing, but 
the
spamops folks have made quite clear that it is both vastly more effort 
and
considerably less productive, than one might expect.

That's a problem with mail relaying in ge! neral, not just with open 
relays.
Now if you want to discourage multi-hop mail relaying, that might actually 
be
useful for lots of reasons besides just traceability.

unfortunately, the vigilante character of various open-relay 
blacklists

blacklists are not the subject of this BCP.

This thread has pretty much diverged from the subject of your draft
document anyway.

killed any attempt at this kind of innovation. just as we're now in
danger of various kinds of brain-dead "authentication" methods and
meaningless requirements killing useful email functionality.

new authentication methods are not the subject of this BCP.

You mean "your draft document". It's certainly not a BCP as it's
currently written.

Keith

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