Re: [Exim] Getting around my isp when they block port 25

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Autor: Leonardo Boselli
Data:  
Dla: exim-users
Temat: Re: [Exim] Getting around my isp when they block port 25
Il 13 Feb 2004 alle 15:27 Greg A. Woods immise in rete
>> On Friday, February 13, 2004 at 16:08:00 (+0100), Leonardo Boselli
>> I think there are three obstacles in doing that:
>> 1. not every DHCP server publicize mx server
> They shouldn't have to if the setting is static for the network you're
> connecting to -- i.e. not dependent on the particular subnet your
> address is assigned at any given time.


I am not considering different subnets for the same provider, but when
one use different providers ad different time (for example whit my
portable i can access to two different networks at workplace, each with
different smarthost, and to three different networks from home, and two
more while mobile. I set the MUA to use always main server at works, with
authentication. Otherwise i would have to switch between 5 to 7 different
setting !)


> > and exim [as well every other MTA/MUA] does not recognize
> > them, so if you are on the move you have to change it every time
> That's only because your system integrator (you? :-) did a very poor
> job of integrating Exim and/or the DHCP client software into your
> system.
> If the DHCP server is advertising MX hosts then it should be trivial
> to have the dhclient software set the right gateway for Exim to use.

Do you have the trivial patch ? It would resolve most of problems.

> > 2. If you use authentication (for example here you can send to
> > internal> distribution list only if you authenticate ...)
> "if ..."? What does this have to do with anything?

If i want to send amessage to some internal distribution list i have to send
the message throught a particular server, using a certain type of
authentication.

> > 3. You lose the control on delivery (for example here if someone
> > send a message can ask the net admin to check if it has been delivered, or
> > if not where is the problem)
> You lost control the moment you agreed to use the network which blocks
> port 25 -- bypassing their rules could very well get you in a great
> deal of trouble, especially if it's a company network with a security
> policy that mandates all e-mail go via authorised company gateways.

Nesessary specification: I am the postmaster for a departmental domain
with about 600 user. It is not uncommon for me to receive request on the
state of delivery of a certain message sent from there ...
> If you want this kind of freedom to manage your own SMTP services than
> you've got to pay for the privilege. I.e. find an ISP who will accept
> your good money to allow you to do what you wish.

An isp in italy did that in 2003. Within one month lost about 30% of its
subscribers.
--
Leonardo Boselli
Nucleo Informatico e Telematico del Dipartimento Ingegneria Civile
Universita` di Firenze , V. S. Marta 3 - I-50139 Firenze
tel +39 0554796431 cell +39 3488605348 fax +39 055495333
http://www.dicea.unifi.it/~leo