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Bill Davidsen | 1 Aug 2002 16:45

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Re: [B5mods] Usefor - submissions to moderated newsgroups.

On Wed, 31 Jul 2002, Russ Allbery wrote:

> > See "2.2. Header Fields" in RFC 2822."
> 
> > So we either deviate or encapsulate.
> 
> No.  That section does not support your contention.  For example, the
> %-escaped form of Newsgroups is entirely compliant with that section.

The problem is that it doesn't properly address the whole header issue, 
the "%" in a "To:" address is parsed by many mailers, such that
  joe%nosuch.com <at> real.com
    -is treated as-
   <at> real.com:joe <at> nosuch.com

and the message is relayed to nosuch.com via the mailer at real.com. Or 
more likely "relaying denied" at real.com these days.

If it weren't for that the % would be acceptable if not ideal. It works 
in all non-address headers AFAIK, if "works" means isn't rejected or 
mangled.

> -- 
> Russ Allbery (rra <at> stanford.edu)             <http://www.eyrie.org/~eagle/>
> 

--

-- 
   -bill davidsen (davidsen <at> prodigy.com)
"The secret to procrastination is to put things off until the
 last possible moment - but no longer"  -me

(Continue reading)

Bernie Cosell | 1 Aug 2002 18:25

Re: [B5mods] Usefor - submissions to moderated newsgroups.

On 1 Aug 2002, at 8:55, Russ Allbery wrote:

> Bill Davidsen <davidsen <at> prodigy.com> writes:
> > On Wed, 31 Jul 2002, Russ Allbery wrote:
> 
> >> No.  That section does not support your contention.  For example, the
> >> %-escaped form of Newsgroups is entirely compliant with that section.
> 
> > The problem is that it doesn't properly address the whole header issue, 
> > the "%" in a "To:" address is parsed by many mailers, such that
> >   joe%nosuch.com <at> real.com
> >     -is treated as-
> >    <at> real.com:joe <at> nosuch.com
> 
> > and the message is relayed to nosuch.com via the mailer at real.com. Or 
> > more likely "relaying denied" at real.com these days.
> 
> We talked this over on USEFOR and don't think it will be a problem.  Those
> sites implementing %-hack only do it for addresses that they consider to
> be local, which means that the only sites that would possibly do this are
> the moderation relay sites.

This is not quite true.  Airnews will *not* accept a post, no matter 
**WHAT** the domain-part of the email address is, if the local-part 
contains either an '!' or '%' and it is not syntatically a correct fake-
uuup or fake-relay email addr.  This has burned me a bunch of times [I 
try to approve a post and $% <at> #$% <at> #$ airnews bounces it because the local 
part doesn't pass their syntatic muster, even though the domain-part is 
clearly elsewhere, and I've argued with them [fruitlessly] that the 
syntax of the local part is none of their business.

(Continue reading)

Russ Allbery | 1 Aug 2002 19:19

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Re: [B5mods] Usefor - submissions to moderated newsgroups.

Bernie Cosell <bernie <at> fantasyfarm.com> writes:

> This is not quite true.  Airnews will *not* accept a post, no matter
> **WHAT** the domain-part of the email address is, if the local-part
> contains either an '!' or '%' and it is not syntatically a correct fake-
> uuup or fake-relay email addr.

Airnews doesn't have to until they start trying to submit posts to
moderated groups with non-ASCII names, at which point they have an
incentive to fix this.

Again, the *only* mail sites that would see addresses with %'s in them are
the moderation relay sites and the news server to which someone posted to
a moderated group with a non-ASCII name.  The moderators themselves would
not see such addresses (they would have already been mapped to the final
address by the relay sites).

--

-- 
Russ Allbery (rra <at> stanford.edu)             <http://www.eyrie.org/~eagle/>

Henry Spencer | 1 Aug 2002 19:08

Re: [B5mods] Usefor - submissions to moderated newsgroups.

On Thu, 1 Aug 2002, Bernie Cosell wrote:
> > sites implementing %-hack only do it for addresses that they consider to
> > be local, which means that the only sites that would possibly do this are
> > the moderation relay sites.
> 
> This is not quite true.  Airnews will *not* accept a post, no matter 
> **WHAT** the domain-part of the email address is, if the local-part 
> contains either an '!' or '%' and it is not syntatically a correct fake-
> uuup or fake-relay email addr.  This has burned me a bunch of times [I 
> try to approve a post and $% <at> #$% <at> #$ airnews bounces it...

But airnews's limitations on email addresses aren't relevant.  The %
appears in an email address only in the proxy email address used to get
stuff to the moderator, never in anything that is fed to the news system. 

                                                          Henry Spencer
                                                       henry <at> spsystems.net

Russ Allbery | 1 Aug 2002 17:55

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Re: [B5mods] Usefor - submissions to moderated newsgroups.

Bill Davidsen <davidsen <at> prodigy.com> writes:
> On Wed, 31 Jul 2002, Russ Allbery wrote:

>> No.  That section does not support your contention.  For example, the
>> %-escaped form of Newsgroups is entirely compliant with that section.

> The problem is that it doesn't properly address the whole header issue, 
> the "%" in a "To:" address is parsed by many mailers, such that
>   joe%nosuch.com <at> real.com
>     -is treated as-
>    <at> real.com:joe <at> nosuch.com

> and the message is relayed to nosuch.com via the mailer at real.com. Or 
> more likely "relaying denied" at real.com these days.

We talked this over on USEFOR and don't think it will be a problem.  Those
sites implementing %-hack only do it for addresses that they consider to
be local, which means that the only sites that would possibly do this are
the moderation relay sites.  That's a fairly small set of sites, and I
think we can just ask them all to turn this off (if they haven't already,
which they probably have since this used to be a huge spam relaying hole).

--

-- 
Russ Allbery (rra <at> stanford.edu)             <http://www.eyrie.org/~eagle/>

Bill Davidsen | 1 Aug 2002 18:46

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Re: [B5mods] Usefor - submissions to moderated newsgroups.

On Thu, 1 Aug 2002, Russ Allbery wrote:

> Bill Davidsen <davidsen <at> prodigy.com> writes:
> > On Wed, 31 Jul 2002, Russ Allbery wrote:
> 
> >> No.  That section does not support your contention.  For example, the
> >> %-escaped form of Newsgroups is entirely compliant with that section.
> 
> > The problem is that it doesn't properly address the whole header issue, 
> > the "%" in a "To:" address is parsed by many mailers, such that
> >   joe%nosuch.com <at> real.com
> >     -is treated as-
> >    <at> real.com:joe <at> nosuch.com
> 
> > and the message is relayed to nosuch.com via the mailer at real.com. Or 
> > more likely "relaying denied" at real.com these days.
> 
> We talked this over on USEFOR and don't think it will be a problem.  Those
> sites implementing %-hack only do it for addresses that they consider to
> be local, which means that the only sites that would possibly do this are
> the moderation relay sites.  That's a fairly small set of sites, and I
> think we can just ask them all to turn this off (if they haven't already,
> which they probably have since this used to be a huge spam relaying hole).

Exactly why it won't be turned off. It is recognized as an attempt to 
relay and the mail is rejected. At least at a few of the major ISPs I 
tried to access. Feel free to try it yourself, but I think "relaying 
denied" rather than "no such user" is a pretty clear indication.

--

--

(Continue reading)

Russ Allbery | 1 Aug 2002 19:16

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Re: [B5mods] Usefor - submissions to moderated newsgroups.

Bill Davidsen <davidsen <at> prodigy.com> writes:
> On Thu, 1 Aug 2002, Russ Allbery wrote:

>> We talked this over on USEFOR and don't think it will be a problem.
>> Those sites implementing %-hack only do it for addresses that they
>> consider to be local, which means that the only sites that would
>> possibly do this are the moderation relay sites.  That's a fairly small
>> set of sites, and I think we can just ask them all to turn this off (if
>> they haven't already, which they probably have since this used to be a
>> huge spam relaying hole).

> Exactly why it won't be turned off. It is recognized as an attempt to
> relay and the mail is rejected. At least at a few of the major ISPs I
> tried to access.

By turned off, I mean not honoring it at all and treating % like any other
local character in the LHS of the address.

I highly doubt it will be a problem.  Most modern MTAs don't even
implement %-hack any more.

--

-- 
Russ Allbery (rra <at> stanford.edu)             <http://www.eyrie.org/~eagle/>

Andrew - Supernews | 6 Aug 2002 00:25

Re: [B5mods] Usefor - submissions to moderated newsgroups.

[removing the moderators list for now]

>>>>> "Russ" == Russ Allbery <rra <at> stanford.edu> writes:

 Russ> I highly doubt it will be a problem.  Most modern MTAs don't
 Russ> even implement %-hack any more.

So far I have one report of failure to mail my andrew%test.invalid
address: from an Earthlink user, with an error message apparently
generated by Earthlink's mail server:

550 <andrew%test.invalid <at> supernews.com> Percent Relaying Denied.

(The server in question claims to be running Sendmail 8.9.3/8.9.3,
but it must be a custom config hack because stock configurations of
the same version do not exhibit the problem.)

--

-- 
Andrew, Supernews
http://www.supernews.com - individual and corporate NNTP services

Graham Drabble | 6 Aug 2002 01:11

Re: [B5mods] Usefor - submissions to moderated newsgroups.

On 05 Aug 2002 "Andrew - Supernews" <andrew <at> supernews.net> wrote in 
news:E17bqIX-000M1g-00 <at> trinity.supernews.net:

> [removing the moderators list for now]
> 
>>>>>> "Russ" == Russ Allbery <rra <at> stanford.edu> writes:
> 
> Russ> I highly doubt it will be a problem.  Most modern MTAs don't
> Russ> even implement %-hack any more.
> 
> So far I have one report of failure to mail my andrew%test.invalid
> address: from an Earthlink user, 

You can add another from a Lineone / Tiscali user. Sending through 
smtp.lineone.net

| MAIL FROM: <graham.drabble <at> lineone.net>
| -> 250 OK
| RCPT TO: <andrew%test.invalid <at> supernews.com>
| -> 550 Administrative prohibition

Claims to be running Exim 4.05.

--

-- 
Graham Drabble
If you're interested in what goes on in other groups or want to find 
an interesting group to read then check news.groups.reviews for what 
others have to say or contribute a review for others to read.

(Continue reading)

Henry Spencer | 1 Aug 2002 19:14

Re: [B5mods] Usefor - submissions to moderated newsgroups.

On Thu, 1 Aug 2002, Bill Davidsen wrote:
> > think we can just ask them all to turn this off (if they haven't already,
> > which they probably have since this used to be a huge spam relaying hole).
> 
> Exactly why it won't be turned off. It is recognized as an attempt to 
> relay and the mail is rejected.

The same effect will be had if you simply treat the % as an ordinary
character, i.e. by completely turning off any special interpretation,
since there will be no such mailbox.

> At least at a few of the major ISPs I tried to access.

The major ISPs are not relevant, unless one of the moderator-proxy sites
happens to be behind one of them.  (The moderator's own site is not, I
believe, relevant -- only the proxy sites, the ones which accept mail to,
e.g. sci-space-tech and forward it to the sci.space.tech moderator, will
ever see the % addresses.) 

                                                          Henry Spencer
                                                       henry <at> spsystems.net

Bill Davidsen | 5 Aug 2002 17:37

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Re: [B5mods] Usefor - submissions to moderated newsgroups.

On Thu, 1 Aug 2002, Henry Spencer wrote:

> On Thu, 1 Aug 2002, Bill Davidsen wrote:
> > > think we can just ask them all to turn this off (if they haven't already,
> > > which they probably have since this used to be a huge spam relaying hole).
> > 
> > Exactly why it won't be turned off. It is recognized as an attempt to 
> > relay and the mail is rejected.
> 
> The same effect will be had if you simply treat the % as an ordinary
> character, i.e. by completely turning off any special interpretation,
> since there will be no such mailbox.
> 
> > At least at a few of the major ISPs I tried to access.
> 
> The major ISPs are not relevant, unless one of the moderator-proxy sites
> happens to be behind one of them.  (The moderator's own site is not, I
> believe, relevant -- only the proxy sites, the ones which accept mail to,
> e.g. sci-space-tech and forward it to the sci.space.tech moderator, will
> ever see the % addresses.) 

The people who use major ISPs might not feel the same way about it. If 
the mailers on the news machines are set to reject relay I don't believe 
they will post to moderated groups using forwarding conventions, or 
anything which looks like a forwarding convention.

Most sites, not only ISPs, are wary of doing anything which might look as if
they let mail out which the recipient site might then relay. After a 
quick check I can say that AIX, Linux, and Solaris all come with "!" and 
"%" configured as significant characters. Do you *really* want to try to

(Continue reading)

Charles Lindsey | 6 Aug 2002 12:02

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Subject: '% in addresses (was [B5mods] Usefor ...)

In <Pine.LNX.3.91.1020805112607.6760C-100000 <at> darkstar.prodigy.com> Bill Davidsen
<davidsen <at> prodigy.com> writes:

Note change of Subject. The [B5mods] Usefor ... thread is mostly
crossposts from the moderators <at> isc.org list (and many of the contributors
are hardly aware it is coming here, yet alone responding to comments
here). This is an issue we need to discuss here.

>Most sites, not only ISPs, are wary of doing anything which might look as if
>they let mail out which the recipient site might then relay. After a 
>quick check I can say that AIX, Linux, and Solaris all come with "!" and 
>"%" configured as significant characters. Do you *really* want to try to 
>convince every site that they should reconfigure sendmail?

Well my sendmail, configured more or less as out of the box, had no
problem sending to Andrew's address. However, I see that some Earthlink
MTA has rejected it, and also a Linone one (using exim apparently).

So what do we do? Look at some oither character?

--

-- 
Charles H. Lindsey ---------At Home, doing my own thing------------------------
Tel: +44 161 436 6131 Fax: +44 161 436 6133   Web: http://www.cs.man.ac.uk/~chl
Email: chl <at> clw.cs.man.ac.uk      Snail: 5 Clerewood Ave, CHEADLE, SK8 3JU, U.K.
PGP: 2C15F1A9      Fingerprint: 73 6D C2 51 93 A0 01 E7 65 E8 64 7E 14 A4 AB A5

Bill Davidsen | 7 Aug 2002 01:13

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Re: Subject: '% in addresses (was [B5mods] Usefor ...)

On Tue, 6 Aug 2002, Charles Lindsey wrote:

> Well my sendmail, configured more or less as out of the box, had no
> problem sending to Andrew's address. However, I see that some Earthlink
> MTA has rejected it, and also a Linone one (using exim apparently).
> 
> So what do we do? Look at some oither character?

Can someone make a QUICK suggestion? I'm looking at my keyboard, and I 
see characters not in my sendmail.cf, but I don't feel confident they 
aren't magic elsewhere in mail, if only as problem causers.

My mail goddess has gone home, all I can do is test against a few 
mailers, none of which objected to ` in an address. Don't take that as a 
recommendation, someone probably doesn't like that either 

I suspect that if there were a better character it would have emerged 18 
months ago. I'd like to look at others, I'm not sure it's going to solve 
anything.

--

-- 
   -bill davidsen (davidsen <at> darkstar.prodigy.com)
"The secret to procrastination is to put things off until the
 last possible moment - but no longer"  -me

Charles Lindsey | 7 Aug 2002 13:03

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Re: Subject: '% in addresses (was [B5mods] Usefor ...)

In <Pine.LNX.3.91.1020806190409.10567F-100000 <at> darkstar.prodigy.com> Bill Davidsen
<davidsen <at> prodigy.com> writes:

>On Tue, 6 Aug 2002, Charles Lindsey wrote:

>> Well my sendmail, configured more or less as out of the box, had no
>> problem sending to Andrew's address. However, I see that some Earthlink
>> MTA has rejected it, and also a Linone one (using exim apparently).
>> 

I am surprised that noone else has come back on this one. Russ? Andrew?

Or do we take the view that the servers that do these stupid things are
broken and can safely be ignored?

>> So what do we do? Look at some oither character?

>Can someone make a QUICK suggestion? I'm looking at my keyboard, and I 
>see characters not in my sendmail.cf, but I don't feel confident they 
>aren't magic elsewhere in mail, if only as problem causers.

>My mail goddess has gone home, all I can do is test against a few 
>mailers, none of which objected to ` in an address. Don't take that as a 
>recommendation, someone probably doesn't like that either 

OK. First of all we require a printable ASCII character, and it MUST NOT
be a valid character in a newsgroup-name, nor must it be a ',' or a '.'.
So that gives us:

! " # $ % & ' ( ) * / : ; < = > ?  <at>  [ \ ] ^ ` { | } ~

(Continue reading)

Claus Färber | 7 Aug 2002 20:04

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Re: Subject: '% in addresses (was [B5mods] Usefor ...)

Charles Lindsey <chl <at> clw.cs.man.ac.uk> schrieb/wrote:
> Now I want to exclude '?', because it is one of the characters that
> introduces an RFC 2047 encoding, and we don't want our encodings to be
> confused with those, do we? Yes, I know that '=' also occurs in RFC 2047
> alongside the '=', but removing one of them is sufficient. Also, I still
> have lingering doubts over '?' in URIs, though it _should_ be unambiguous
> there.

> $ & ' = ^ ~

Not that "&" is unwise as some people are too stupid to write it
correctly within HTML (i.e. as "&amp;").
Further, the "?" is used to seperate the address part from a query part,
which is also used in mailto URIs to seperate the address from further
paramters (e.g. mailto:me <at> example.com?subject=foo).

Further, the "=" is used to seperate hname from hvalue in RFC 2368 URLs,
so it has to be encoded in RFC 2386 URLs where an address appears in an
parameter, e.g. (mailto:?to=de-l%3dE4rm <at> example.com). This, of course  
does not mean that "=" can't be used; it's still one of the best  
characters.

Claus
--

-- 
------------------------ http://www.faerber.muc.de/ ------------------------
OpenPGP: DSS 1024/639680F0 E7A8 AADB 6C8A 2450 67EA AF68 48A5 0E63 6396 80F0

Henry Spencer | 7 Aug 2002 15:26

Re: Subject: '% in addresses (was [B5mods] Usefor ...)

On Wed, 7 Aug 2002, Charles Lindsey wrote:
> Or do we take the view that the servers that do these stupid things are
> broken and can safely be ignored?

As per Russ's comment this morning, the problem is much less serious than
it might superficially appear, and it *can* safely be ignored.

I agree with Charles's reasoning that `=' is probably the best replacement
for `%', but I don't think the change is necessary.  I have a harder time
deciding whether it is desirable anyway; on balance I think not.

                                                          Henry Spencer
                                                       henry <at> spsystems.net

Andrew - Supernews | 5 Aug 2002 19:07

Re: [B5mods] Usefor - submissions to moderated newsgroups.

Bill Davidsen <davidsen <at> prodigy.com>:
> The people who use major ISPs might not feel the same way about
> it. If the mailers on the news machines are set to reject relay
> I don't believe they will post to moderated groups using
> forwarding conventions, or anything which looks like a
> forwarding convention.

please substitute actual knowledge for your "belief". Feel free to
use the <andrew%test.invalid <at> supernews.com> address for testing
purposes; it now has a simple autoresponder on it. (Note that it
will reply _only once_ to any given Reply-To address.)

> Most sites, not only ISPs, are wary of doing anything which
> might look as if they let mail out which the recipient site
> might then relay. After a quick check I can say that AIX,
> Linux, and Solaris all come with "!" and "%" configured as
> significant characters. Do you *really* want to try to convince
> every site that they should reconfigure sendmail?

they don't need to reconfigure sendmail. The % character is only
significant in _local_ addresses; that's why it works as a routing
hack in the first place. Stock sendmail configurations will handle
mail to the address given above without problems (a couple of people
have tested it in addition to me).

If you know of any site which is not capable of sending mail to a
remote address containing '%' in the local part then please be
specific.

If anyone gets a bounce message from attempting to mail the address

(Continue reading)

Andrew - Supernews | 1 Aug 2002 19:46

Re: [B5mods] Usefor - submissions to moderated newsgroups.

[ % in addresses ]

FWIW, I tested this here (we are now a moderator relay site). Our mail
system (a pretty straightforward Exim setup) needed no configuration
changes in order to handle an alias containing %. I've then tried
mailing the alias I created (<andrew%test.invalid <at> supernews.com> if
anyone else wants to try it out) from a couple of stock Sendmail
systems, without any problems.

--

-- 
Andrew, Supernews
http://www.supernews.com - individual and corporate NNTP services

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