there is at least one reason for not sending email directly:
if the server IP address is added to some blacklist like SORBS, the notification is sent to the contact address of the reverse zone. If the server is under the ISP's maintenance, the ISP will (supposedly) notice this event and try its best (haha) to remove the server address from that blacklist.
If the end-user's fixed IP address appears in SORBS list, the user will not notice it, and it will take much more time before it's removed.
interesting, is there a business case behind? How much would one pay for a reliable and SORBS-free mail relay service? It's actually quite easy to build :)
----- Original Message ----
From: Per Jessen per.jessen@enidan.ch To: swinog@lists.swinog.ch Sent: Thursday, September 11, 2008 12:58:40 PM Subject: Re: [swinog] Anyone from Green here?
Stanislav Sinyagin wrote:
Anyway, who's going to send email directly from a broadband connection, instead of using the ISP's relay? :-)
Provided everything is properly set up, why shouldn't they?
Stanislav Sinyagin wrote:
there is at least one reason for not sending email directly:
if the server IP address is added to some blacklist like SORBS, the notification is sent to the contact address of the reverse zone. If the server is under the ISP's maintenance, the ISP will (supposedly) notice this event and try its best (haha) to remove the server address from that blacklist.
If the end-user's fixed IP address appears in SORBS list, the user will not notice it, and it will take much more time before it's removed.
I dunno - those are two big if's, and neither makes much of a reason for not sending email directly. I think it's fairly safe to say that _nobody_ is notified automagically just because an IP is added to some arbitrary blacklist.
/Per Jessen, Herrliberg
On Thu, Sep 11, 2008 at 04:32:50AM -0700, Stanislav Sinyagin wrote:
if the server IP address is added to some blacklist like SORBS, the notification is sent to the contact address of the reverse zone.
A properly managed mail server's admin would notice that quite quickly. Infact, I(*) have been listed in ORBS or others in the last few years, usually because of an automated Mailman answer to some spam coming from a spam-trap address, and each time, it was my duty to unlist me, and sometimes ask my service provider to send a nice e-mail.
I am a heavy users of those RBL lists, they offer quite a bit of protection (but not as much as you might think, and with quite a few false positives: greylisting is much more efficient).
If the server is under the ISP's maintenance, the ISP will (supposedly) notice this event and try its best (haha) to remove the server address from that blacklist.
... supposedly.
The reason why the customer doesn't want to go through smtp.green.ch anyway is because green apparently runs a non standard Microsoft SMTP server which has the interesting property of either dropping mails silently, or, more frequently, bouncing them as spam.
Contacting green support personal was replied with "it's the remote SMTP destination which refuses the mail, not us" -- although sending directly to the remote SMTP destination works. So it must be a modification made by the non standard Microsoft SMTP server which triggers the problem at the remote site, or they can't read their own logs.
However, some (other) SMTP servers will refuse mail directly coming from this customer because it has reverse PTR not in the domain.
The temporary workaround for this was to use yet-another-smart-host from another company, not green they have a subscription to. This works quite well, but is a bit puzzling.
(*) happy net2000 (cablecom) customer, with properly set up reverse, thanks net2000.
The last issue I had recently is with Yahoo delaying some of the messages sent to mailing-lists I host, I had to go through an interesting procedure during the last few months to be able to get the opportunity of maybe getting delisted, including a Privacy policy (http://www.alphanet.ch/privacy_policy.html if you are interested).
Marc SCHAEFER wrote: [..]
I am a heavy users of those RBL lists, they offer quite a bit of protection (but not as much as you might think, and with
You should use RBL's only for *scoring*; not for decision making and then directly rejecting based on it.
quite a few false positives: greylisting is much more efficient).
Greylisting only delays mails. Proper spammers just use ISP relays and then they will try forever. Or they will just nicely do the full SMTP thing for the first message and try again later, or stall sending to you as the 450 is recognized and spam run you again later. So many easy ways around it and it only causes annoyance.
On top of that, I guess you have whitelisted large mail providers like gmail who try to send a single mail from several IP's, thus hitting your greylist over and over again, and then just giving up? :)
[..]
The last issue I had recently is with Yahoo delaying some of the messages sent to mailing-lists I host, I had to go through an interesting procedure during the last few months to be able to get the opportunity of maybe getting delisted, including a Privacy policy (http://www.alphanet.ch/privacy_policy.html if you are interested).
When you send mail (or packets for that matter) to a remote site, that remote site can deny/filter/mangle those packets every way they want. As long as you are a smaller fish then them and you want to still deliver packets/mail to them you will have to comply to their rules.
But as you are doing greylisting yourself, why are you complaining about another little bit of delay? ;)
As always, it is your site, thus any problems you make for yourself are, well, made for yourself ;)
Greets, Jeroen
Jeroen Massar schrieb:
Marc SCHAEFER wrote: [..]
I am a heavy users of those RBL lists, they offer quite a bit of protection (but not as much as you might think, and with
You should use RBL's only for *scoring*; not for decision making and then directly rejecting based on it.
In Switzerland, you can whitelist most of the "known-good" (dynamic) IP address ranges (and important mailservers) quite easily with a mixture of the list provided by the swinog-RBL and some historic data. There rest is dealt with a few customer-support tickets. That's the beauty of Switzerland - it's so small ;-)
Rainer
great idea, whitelisting every system on the world which sends confirmation email .. it will be an big efford for that small country to convince the rest of the world ;-)
Jeroen Massar schrieb:
Marc SCHAEFER wrote: [..]
I am a heavy users of those RBL lists, they offer quite a bit of protection (but not as much as you might think, and with
You should use RBL's only for *scoring*; not for decision making and then directly rejecting based on it.
In Switzerland, you can whitelist most of the "known-good" (dynamic) IP address ranges (and important mailservers) quite easily with a mixture of the list provided by the swinog-RBL and some historic data. There rest is dealt with a few customer-support tickets. That's the beauty of Switzerland - it's so small ;-)
Rainer _______________________________________________ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
Am 11.09.2008 um 20:28 schrieb roger@mgz.ch:
great idea, whitelisting every system on the world which sends confirmation email .. it will be an big efford for that small country to convince the rest of the world ;-)
To be precise: I use dnsbl.sorbs.net to blacklist all dynamic IPs (and the RBL from spamcop, and also the swinog RBL - I would use spamhaus, but they blocked us because we make too many requests and we can't afford their prices). Then, I use the list on the SWINOG-RBL homepage to whilelist all the swiss dynamic IPs (and some other big systems, plus various IPs clients requested us to whitelist over the years) - because those are the one's that may actually want to relay through our system or send us mail legitimately. senderbase.org helps finding IPs of outbound relays, too.
I don't use greylisting - IMO, it's a system that doesn't work large- scale, in a similar way TMDA or other "please reply to this email or click on this link"-systems don't work in practise.
To be vaguely on topic - most of our customers have static IPs, and it's not a problem to set the PTR to another value. But we also don't boast 100000+ customers, like www.green.ch does - maybe they're afraid of having to change 100k PTRs, if they set a precedent? ;-)
IT would be so easy - it's just users and customers that make it difficult :-)))
Rainer
-
Jeroen Massar -
Marc SCHAEFER -
Per Jessen -
Rainer Duffner -
roger＠mgz.ch -
Stanislav Sinyagin