Re: [courier-users] Address literals

2016-07-31 Thread Sam Varshavchik 

Alessandro Vesely writes:


On Sat 30/Jul/2016 14:30:18 +0200 Sam Varshavchik wrote:
> Matus UHLAR - fantomas writes:
>> On 29.07.16 06:48, Sam Varshavchik wrote:
>>> Courier should accept postmaster@[ipaddress], where ipaddress matches
>>> the connection's IP address. It won't accept any other IP address.

That means ipaddress matches the /local side/ of the connection if the mail
address is a recipient, right?


You don't know who the recipient is until you check the domain.


>> what about servers behind DNAT?
>
> That's obviously a problem. But this problem is due to DNAT itself.
>
> If a mail server accepts any IP address, delivers locally for its own IP
> address, and relays everything else, DNAT will still be a problem there. A  
mail
> addressed to postmaster@[public ip address] which reach the server, which  
will

> promptly attempt to relay it.

Reverse lookup can be used to learn which domain's postmaster that would be,


That might be possible. The current implementation always uses the  
configured local domain (defaultdomain).


> I would also have to question whether anyone cares a lot about this legacy  
SMTP

> feature.

It is meant as a last resort, in case there's something wrong in the DNS.  An
extra bit of resiliency, which would almost never be used.


Well, what it's meant to be is one thing. What it actually is, is something  
that I would be surprised if it works correctly for more than one in a  
thousand domains, with the definition of "works" meaning that the mail gets  
delivered to someone who actually looks at it.




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Re: [courier-users] Address literals

2016-07-31 Thread Matus UHLAR - fantomas 
>>On 29.07.16 06:48, Sam Varshavchik wrote:
>>>Courier should accept postmaster@[ipaddress], where ipaddress matches
>>>the connection's IP address. It won't accept any other IP address.

>Matus UHLAR - fantomas writes:
>>what about servers behind DNAT?

On 30.07.16 08:30, Sam Varshavchik wrote:
>That's obviously a problem. But this problem is due to DNAT itself.
>
>If a mail server accepts any IP address, delivers locally for its own 
>IP address, and relays everything else, DNAT will still be a problem 
>there. A mail addressed to postmaster@[public ip address] which reach 
>the server, which will promptly attempt to relay it.

hmmm list of local ip addresses could do that.
maybe in the "hosteddomains" file, although I would prefer defining it in
virtualdomains and only configured postmaster@ in those domains

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Re: [courier-users] Address literals

2016-07-31 Thread Alessandro Vesely 
On Sat 30/Jul/2016 14:30:18 +0200 Sam Varshavchik wrote:
> Matus UHLAR - fantomas writes:
>> On 29.07.16 06:48, Sam Varshavchik wrote:
>>> Courier should accept postmaster@[ipaddress], where ipaddress matches
>>> the connection's IP address. It won't accept any other IP address.

That means ipaddress matches the /local side/ of the connection if the mail 
address is a recipient, right?

>> what about servers behind DNAT?
>
> That's obviously a problem. But this problem is due to DNAT itself.
>
> If a mail server accepts any IP address, delivers locally for its own IP
> address, and relays everything else, DNAT will still be a problem there. A 
> mail
> addressed to postmaster@[public ip address] which reach the server, which will
> promptly attempt to relay it.

Reverse lookup can be used to learn which domain's postmaster that would be, as 
it is always possible to configure local views of private addresses.  If rDNS 
works, the domain name can replaced the IP address and the message delivered 
accordingly.  If rDNS doesn't work, relay to ipaddress:25 but drop the literal 
domain from the recipient email address.  Would that work?

> If the mail server ignores the IP address, then the mail server itself cannot
> be used to relay mail for postmaster@[some public ip address].

Yes, it doesn't make sense to relay and deliver at the same time.  I put the 
question to the SMTP interest list:
https://mailarchive.ietf.org/arch/msg/ietf-smtp/Afx85GoYWIRzy6vAQkzJ0hzE10s

> I would also have to question whether anyone cares a lot about this legacy 
> SMTP
> feature.

It is meant as a last resort, in case there's something wrong in the DNS.  An 
extra bit of resiliency, which would almost never be used.

Ale
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Re: [courier-users] Address literals

2016-07-30 Thread Sam Varshavchik 

Alessandro Vesely writes:


On Fri 29/Jul/2016 12:48:25 +0200 Sam Varshavchik wrote:
> Alessandro Vesely writes:
>
>> SMTP provides for:
>>
>> address-literal  = "[" ( IPv4-address-literal /
>>  IPv6-address-literal /
>>  General-address-literal ) "]"
>>  ; See Section 4.1.3
>>
>> Mailbox= Local-part "@" ( Domain / address-literal )
>>
>> However, Courier gives a syntax error:
>>
>> >>> rcpt to:
>> <<< 513 Syntax error.
>>
>> Has it always been so?  Why?
>
> Courier should accept postmaster@[ipaddress], where ipaddress matches the
> connection's IP address. It won't accept any other IP address.

Irrespectively or RELAYCLIENT?


Yes, because the recipient address is local.



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Re: [courier-users] Address literals

2016-07-30 Thread Sam Varshavchik 

Matus UHLAR - fantomas writes:


>Alessandro Vesely writes:
>>SMTP provides for:
>>
>>address-literal  = "[" ( IPv4-address-literal /
>> IPv6-address-literal /
>> General-address-literal ) "]"
>> ; See Section 4.1.3
>>
>>Mailbox= Local-part "@" ( Domain / address-literal )
>>
>>However, Courier gives a syntax error:
>>
>>>>> rcpt to:
>><<< 513 Syntax error.
>>
>>Has it always been so?  Why?

On 29.07.16 06:48, Sam Varshavchik wrote:
>Courier should accept postmaster@[ipaddress], where ipaddress matches
>the connection's IP address. It won't accept any other IP address.

what about servers behind DNAT?


That's obviously a problem. But this problem is due to DNAT itself.

If a mail server accepts any IP address, delivers locally for its own IP  
address, and relays everything else, DNAT will still be a problem there. A  
mail addressed to postmaster@[public ip address] which reach the server,  
which will promptly attempt to relay it.


If the mail server ignores the IP address, then the mail server itself  
cannot be used to relay mail for postmaster@[some public ip address].


I would also have to question whether anyone cares a lot about this legacy  
SMTP feature.




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Re: [courier-users] Address literals

2016-07-30 Thread Alessandro Vesely 
On Fri 29/Jul/2016 19:16:48 +0200 Matus UHLAR - fantomas wrote:
>>On Fri 29/Jul/2016 12:48:25 +0200 Sam Varshavchik wrote:
>>> Courier should accept postmaster@[ipaddress], where ipaddress matches the
>>> connection's IP address. It won't accept any other IP address.
>
> On 29.07.16 18:41, Alessandro Vesely wrote:
>> Irrespectively or RELAYCLIENT?
>
> I actually don't think tht RELAYCLIENT should be taken into account.
> if the client has relaying privileges, (s)he should know hot co contact the
> server admin(s)

I tried is to send a complaint to 187.115.25.174.  I tried to send to the 
registered WHOIS address, but got:

  :
  mxin1.gvt.com.br [200.175.5.1]:
  >>> DATA
  <<< 554 rejecting banned content

Nothing bad with the content, it was just message/rfc822, 
message/delivery-status, and text/plain.  Hence their site is obviously badly 
configured --which was the object of the original complaint.  Reverse lookup 
doesn't work either (NOT SYNC ZONE), so I don't know how to contact site 
admins.  One possibility is to just dial 187.115.25.174:25 and ask for 
postmaster...

Ale
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Re: [courier-users] Address literals

2016-07-29 Thread Matus UHLAR - fantomas 
>On Fri 29/Jul/2016 12:48:25 +0200 Sam Varshavchik wrote:
>> Courier should accept postmaster@[ipaddress], where ipaddress matches the
>> connection's IP address. It won't accept any other IP address.

On 29.07.16 18:41, Alessandro Vesely wrote:
>Irrespectively or RELAYCLIENT?

I actually don't think tht RELAYCLIENT should be taken into account.
if the client has relaying privileges, (s)he should know hot co contact the
server admin(s)
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Re: [courier-users] Address literals

2016-07-29 Thread Alessandro Vesely 
On Fri 29/Jul/2016 12:48:25 +0200 Sam Varshavchik wrote:
> Alessandro Vesely writes:
>
>> SMTP provides for:
>>
>> address-literal  = "[" ( IPv4-address-literal /
>>  IPv6-address-literal /
>>  General-address-literal ) "]"
>>  ; See Section 4.1.3
>>
>> Mailbox= Local-part "@" ( Domain / address-literal )
>>
>> However, Courier gives a syntax error:
>>
>> >>> rcpt to:
>> <<< 513 Syntax error.
>>
>> Has it always been so?  Why?
>
> Courier should accept postmaster@[ipaddress], where ipaddress matches the
> connection's IP address. It won't accept any other IP address.

Irrespectively or RELAYCLIENT?

Ale


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Re: [courier-users] Address literals

2016-07-29 Thread Matus UHLAR - fantomas 
>Alessandro Vesely writes:
>>SMTP provides for:
>>
>>address-literal  = "[" ( IPv4-address-literal /
>> IPv6-address-literal /
>> General-address-literal ) "]"
>> ; See Section 4.1.3
>>
>>Mailbox= Local-part "@" ( Domain / address-literal )
>>
>>However, Courier gives a syntax error:
>>
>>>>> rcpt to:
>><<< 513 Syntax error.
>>
>>Has it always been so?  Why?

On 29.07.16 06:48, Sam Varshavchik wrote:
>Courier should accept postmaster@[ipaddress], where ipaddress matches 
>the connection's IP address. It won't accept any other IP address.

what about servers behind DNAT?

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Re: [courier-users] Address literals

2016-07-29 Thread Sam Varshavchik 

Alessandro Vesely writes:


SMTP provides for:

address-literal  = "[" ( IPv4-address-literal /
 IPv6-address-literal /
 General-address-literal ) "]"
 ; See Section 4.1.3

Mailbox= Local-part "@" ( Domain / address-literal )

However, Courier gives a syntax error:

>>> rcpt to:
<<< 513 Syntax error.

Has it always been so?  Why?


Courier should accept postmaster@[ipaddress], where ipaddress matches the  
connection's IP address. It won't accept any other IP address.




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[courier-users] Address literals

2016-07-29 Thread Alessandro Vesely 
SMTP provides for:

address-literal  = "[" ( IPv4-address-literal /
 IPv6-address-literal /
 General-address-literal ) "]"
 ; See Section 4.1.3

Mailbox= Local-part "@" ( Domain / address-literal )

However, Courier gives a syntax error:

>>> rcpt to:
<<< 513 Syntax error.

Has it always been so?  Why?

Ale


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