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Old 04-20-2010, 09:57 PM
Stroller
 
Default Setting up a fall back ISP SMTP in sendmail

On 20 Apr 2010, at 14:53, Harry Putnam wrote:


I think you all are missing something... sendmail is better documented
than any of the other pretenders.
...
Unless, I'm terribly misinformed, sendmail is still the most commonly
used mta in the unix world of servers.


I would be surprised if it is better documented or more widely used
than Postfix.


(Although I have to admit I find Postfix documentation difficult, IMO
his is because it's so flexible & powerful).


Stroller.
 
Old 04-20-2010, 09:59 PM
Stroller
 
Default Setting up a fall back ISP SMTP in sendmail

On 19 Apr 2010, at 22:50, Mick wrote:

...
The problem is that you'll spend an hour or two setting it all up,
it'll work,
you'll never touch it again. Then, two years later something will
require you

to reconfigure it and there will be no way on this earth that you will
remember what you did or why it made any sense at the time! Ha,
ha! :-))


To be fair, is this not mostly the case with the majority of big,
powerful servers on *nix platforms?


I have certainly found this to be the case with Apache, Postfix and to
a lesser extend Samba. Oh! Also syslog-ng's filtering options. The
only text-based configuration file I've found easy to recreate has
been that of Dovecot.


Stroller.
 
Old 04-21-2010, 10:18 AM
Alan McKinnon
 
Default Setting up a fall back ISP SMTP in sendmail

On Tuesday 20 April 2010 15:53:01 Harry Putnam wrote:
> I think you all are missing something... sendmail is better documented
> than any of the other pretenders.

One has to understand what the various MTAs out there were built to do, and
what their "feature list" is:

sendmail comes from ancient days. It was written to be able to route almost
any kind of mail using almost any kind of addressing scheme to and from almost
any kind of network. So it is quite happy receiving SMTP mail from the
internet and routing it to a FidoNet address. To do this, it has to reread
it's routing table with every message, therefore .cf was designed to be
machine efficient but still use only ASCII characters. Which led to m4 being
developed to make it easier, and I've even seen more simple apps that are
front ends to m4. After a while you start asking "Wow, is this complexity
actually needed?"

Postfix was designed to remove the sendmail complexity from a sysadmin's life
while still being somewhat familiar. It's claim to fame is the ability to pump
enormous amounts of mail down a pipe and keep the routing rules simple. I have
two Postfix relays, both of them can deal with 3 million mails a day without
breaking a sweat. Let me put that in perspective, it's about 30 mails a
second, every second. Postfix is so good at this, I can run them as VMWare
virtual machine.

exim doesn't fare quite as well as Postfix in the raw throughput department,
but it is very very good at giving the sysadmin efficient filtering/routing
rules.

qmail is, how shall I put this? Something that Dan wrote? Dan likes to find
fault in the detail with almost all software and likes to perform experiments
to prove himself right. He also likes to do all of this his own way with the
result that his stuff is a square peg and you have a round hole. Most
sysadmins I know consider the pain of using qmail to not offset the benefit of
using qmail, therefore they don't use it.

> Now understand, that I am easily the dullest knife in the drawer on
> this list even though by unix/linux standards I'm fairly long in the
> tooth having started my computing skills in 1996 and broke in on
> redhat at that time (using sendmail). I'm sad to say, I'm still a
> noob in a vast number of areas.
>
> I've used sendmail all that time. If I can figure out how to use
> it.... It really must not be that hard. At least not hard to find
> piles of help on google.

Postfix's web site has an enormous amount of documentation on everything
related to Postfix.

> Admittedly though my usage has always been just a homeboy home lan
> administrator so closest I ever come to using sendmail anything like
> what its target usage base is, would be a home lan mailhub.
>
> Unless, I'm terribly misinformed, sendmail is still the most commonly
> used mta in the unix world of servers.

Yes, you are misinformed. My logs show very little mail being received from
sendmail MTAs. There may well be large numbers of ancient sendmail installs
out there, but they do not account for a large fraction of the mail being
sent. That trophy belongs to Windows zombie bots....

> At least according to http://en.wikipedia.org/wiki/Sendmail
>
> Qmail home page says it is the second most common MTA but doesn't say
> who is first.... its sendmail... I'm pretty sure.
>
> About all the snipes concerning hacking sendmail.cf... I'm sure you
> are all aware that any hacking needs to happen in sendmail.mc... then
> let m4 sort out sendmail.cf.

Even a cursory glance at sendmail shows that it was designed in a time with a
different mindset and different needs to what we do these days. Sendmail will
never escape this legacy because it is what it is and that is it's purpose.

It's not as bad as buggy whips, but the same principle is at work.

--
alan dot mckinnon at gmail dot com
 
Old 04-21-2010, 10:22 AM
Alan McKinnon
 
Default Setting up a fall back ISP SMTP in sendmail

On Tuesday 20 April 2010 17:51:12 Harry Putnam wrote:
> Grant Edwards <grant.b.edwards@gmail.com> writes:
> > On 2010-04-20, Harry Putnam <reader@newsguy.com> wrote:
> >> About all the snipes concerning hacking sendmail.cf... I'm sure you
> >> are all aware that any hacking needs to happen in sendmail.mc... then
> >> let m4 sort out sendmail.cf.
> >
> > IOW, sendmail has a configuration file so incomprehensible that the
> > configuration file needs a configuration file.
>
> Internet mail is quite complex, yes.

This statement is the source of the confusion surrounding sendmail.

Internet mail is not complex, it is stunningly simple:

mail comes in,
look up where it should go,
send it there

In between you might hand the message off to virus and spam scanners, you
might look up an ACL before accepting it coming in, but those are all
additives to find valid mail. Remove the additives, and you get the amazingly
simple lookup table scheme described above.

There isn't even an inherent difference between relays and final destination
MTAs, they still send the mail somewhere. The difference is in the viewpoint
of the sysadmin.


--
alan dot mckinnon at gmail dot com
 
Old 04-21-2010, 02:19 PM
Grant Edwards
 
Default Setting up a fall back ISP SMTP in sendmail

On 2010-04-21, Alan McKinnon <alan.mckinnon@gmail.com> wrote:
> On Tuesday 20 April 2010 15:53:01 Harry Putnam wrote:
>> I think you all are missing something... sendmail is better documented
>> than any of the other pretenders.
>
> One has to understand what the various MTAs out there were built to do, and
> what their "feature list" is:
>
> sendmail comes from ancient days. It was written to be able to route almost
> any kind of mail using almost any kind of addressing scheme to and from almost
> any kind of network.

Very true. And since nobody (that I know of) needs that capability
any longer, asking modern Linux users to continue to pay for that
capability everytime they try to tweak the MTA configuration seems a
tad silly.

> So it is quite happy receiving SMTP mail from the internet and
> routing it to a FidoNet address. To do this, it has to reread it's
> routing table with every message, therefore .cf was designed to be
> machine efficient but still use only ASCII characters. Which led to
> m4 being developed

Sendmail didn't lead to m4 being developed. m4 was developed by K&R
in the mid 70's. Sendmail didn't happen until the early 80's.
According to Wikipedia, sendmail first shipped with BSD 4.1c in 1983.

Unless in this context, m4 doesn't refer to the m4 macro processor and
associated language? I always thought that the m4 used to encrypt
sendmail configurations was the standard Unix m4 that was developed
for Ratfor in the 70's. Wikipedia seems to confirm that, saying that
"The implementation of Rational Fortran used m4 as its macro engine
from the beginning", but Wikipedia also says that m4 was developed in
77 and Ratfor in 74. Both were developed by K&R, so I suppose it
could be that m4 was used by Ratfor for a couple years before m4 went
public as a seperate program.

> Even a cursory glance at sendmail shows that it was designed in a
> time with a different mindset and different needs to what we do these
> days. Sendmail will never escape this legacy because it is what it is
> and that is it's purpose.
>
> It's not as bad as buggy whips, but the same principle is at work.

The UHH chapter on sendmail has some great examples of sendmail
address parsing/transformation run amok.

--
Grant Edwards grant.b.edwards Yow! My polyvinyl cowboy
at wallet was made in Hong
gmail.com Kong by Montgomery Clift!
 
Old 04-23-2010, 12:23 AM
Harry Putnam
 
Default Setting up a fall back ISP SMTP in sendmail

Alan McKinnon <alan.mckinnon@gmail.com> writes:

> On Tuesday 20 April 2010 15:53:01 Harry Putnam wrote:
>> I think you all are missing something... sendmail is better documented
>> than any of the other pretenders.
>
> One has to understand what the various MTAs out there were built to do, and
> what their "feature list" is:
>
> sendmail comes from ancient days. It was written to be able to route almost

As ancient as 2007, at least one survey shows sendmail as still the
most popular.

One fairly recent survey sited on wikipedia shows sendmail as losing ground
but still the most popular MTA.. at 29% of the surveyed market. Down
from some 42% in 2001/3

That's a lot of `buggy whips'.

http://en.wikipedia.org/wiki/Sendmail

[...]

In 2001, approximately 42% of the publicly-reachable mail-servers on
the Internet ran Sendmail.[1] More recent surveys have suggested a
decline, with 29.4% of mail servers in August 2007 detected as
running Sendmail in a study performed by E-Soft, Inc.[2] Sendmail is
trailed by Microsoft Exchange Server, Exim, and Postfix; these four
being the only mail servers with more than 10% of the total.

[...]
 
Old 04-23-2010, 12:25 AM
Harry Putnam
 
Default Setting up a fall back ISP SMTP in sendmail

Alan McKinnon <alan.mckinnon@gmail.com> writes:

>> Internet mail is quite complex, yes.

> This statement is the source of the confusion surrounding sendmail.

> Internet mail is not complex, it is stunningly simple:

> mail comes in,
> look up where it should go,
> send it there

[...]

Egad, I had no idea it was so simple; maybe you should tell all those
guys who collaborate in writing piles of rfcs that pertain to
internet mail and related issues, I bet they don't know it so easy
either.
 

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