<div dir="ltr"><br><div class="gmail_extra"><br><br><div class="gmail_quote">On 30 April 2013 09:49, Jonas Akrouh Larsen <span dir="ltr"><<a href="mailto:jonas@vrt.dk" target="_blank">jonas@vrt.dk</a>></span> wrote:<br>
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<p class="MsoNormal"><span lang="EN-US" style>Hi Glenn<u></u><u></u></span></p><div class="im">
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<p class="MsoNormal"><span lang="EN-US" style><u></u> <u></u></span></p>
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<p class="MsoNormal"><span lang="EN-US" style>>That MailScanner doesn't operate at SMTP-time is exactly what sets it apart... It is the fundamental difference that make MailScanner perform so >much better, and suffer from so much less risk of
DoS:ing, than amavisd ...<u></u><u></u></span></p>
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<p class="MsoNormal"><span lang="EN-US" style>>Sure, you cannot do "on the fly rejections", but ... AV/Anti-UCE scanning is to expensive at that stage anyway (IMO)... apart from the simple >things you can do in the MTA, that is (recipient verification,
rfc strictness, graylisting etc). But the benefits of not doing it in one go, as amavisd >does, far outweigh that drawback.<u></u><u></u></span></p>
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<p class="MsoNormal"><span lang="EN-US" style>>If one were to somehow wrangle MailScanner into action during SMTP... one could as well use amavisd instead;-).<u></u><u></u></span></p>
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<p class="MsoNormal"><span lang="EN-US" style>>As for choice of MTA, one should always stick with the one one is most comfortable with ... You're far less likely to foobar things if you know >what you're doing:-). If one starts from scratch, taking
into account what happens to be the default on the system you use seem like a very sound >strategy:-).<u></u><u></u></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif"">I’ve stuck with exim+MS for 5 years so I guess I must be liking it for the most part
</span><span style="font-size:11.0pt;font-family:Wingdings">J</span><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif""><u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif""><u></u> </span></p></div></div></div></blockquote><div style>For the most pat, yes...:-)</div><div style>
Have been using Postfix/MS for close to 10 years myself. Still a happy customer;-).</div><div style><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="DA" link="blue" vlink="purple">
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif"">However I do find it annoying not being able to scan at smtp time, it would be much simpler for bounces and such, and rid my outgoing queue of mails
I can’t return to sender because it was forged etc.<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif""><u></u> </span></p></div></div></div></blockquote><div style>With the numbers you quote in a later response in this thread (20k/day with about 20-40 bouces "living" in your outgoing queue at any given moment), it doesn't sound that bad... Sure, one *could* miss something important in theoutgoing queue, but ... once you look there, you tend to know that you're looking for, wouldn't you say?;-).</div>
<div style><br></div><div style>You mention a few of these are due to systems downstream doing 4xx temp failures, or similar... The way I work around this is by not doing a normal "call ahead recipient verification", but rather maintain a relay recipient file that I recreate (if the downstream hosts are available) every 15 minutes... That way, the normal scanning will take place as long as my MX doesn't run out of disk for the queues. Don't know if this is easily done in exim, but is rather trivial with postfix.</div>
<div style>And yes, I do realize that doing things like that isn't optimal for a service provider type of setup. But for the corporate side of things... It just works dandily:-)</div><div style><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Also it shouldn’t run in parallel, so it’s no more expensive than running it post smtp, since you don’t spam scan a virus, you don’t virusscan something
listed on rbl etc.<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif""><u></u></span></p></div></div></div></blockquote><div style><br></div><div style>But the thing is, with the load you describe, you very likely do have batches larger than 1 message/batch... If you do "MS scanning" at SMTP-time, you will not be able to do that. Sure, you'd still "gain" the intelligent order of execution MS has, but ... you'd miss out on the truly impressive performance gain you have in the batching.</div>
<div style>Also... Don't underestimate the DoS risk... While under fire on a normal MS setup, the queue storage is likely to run out before the system croaks due to processing ... overload ... Do MS at SMTP and the system will likely go into memory deprivation/thrashing or plain run out of CPU before anything like that can happen... IMO, that is:-).</div>
<div style><br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="DA" link="blue" vlink="purple"><div><div><p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif""> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif"">But thanks for the comments
</span><span lang="EN-US" style="font-size:11.0pt;font-family:Wingdings">J</span><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif""><u></u><u></u></span></p><div class="im">
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif""><u></u> </span></p></div></div></div></div></blockquote><div style>You're welcome. </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div lang="DA" link="blue" vlink="purple"><div><div><div class="im"><p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif""><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Med venlig hilsen / Best regards<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif""> </span></p></div></div></div></div></blockquote><div style>Vänlig hälsning till dig med!</div><div style>
Cheers</div><div style>-- </div><div style>-- Glenn </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="DA" link="blue" vlink="purple"><div><div><div class="im">
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif""><u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Jonas Akrouh Larsen<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri","sans-serif""> <u></u><u></u></span></p>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br>-- Glenn<br>email: glenn < dot > steen < at > gmail < dot > com<br>work: glenn < dot > steen < at > ap1 < dot > se
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