OT Sendmail configuration question

Jim Dickenson dickenson at CFMC.COM
Sat Feb 12 00:16:15 GMT 2005

Thanks very much. This looks like what I was looking for. If you do not know
what to search for it is real hard to find it.

Thanks for the info
Jim Dickenson
mailto:dickenson at cfmc.com


> From: John Rudd <jrudd at UCSC.EDU>
> Reply-To: MailScanner mailing list <MAILSCANNER at JISCMAIL.AC.UK>
> Date: Fri, 11 Feb 2005 15:32:55 -0800
> Subject: Re: OT Sendmail configuration question
> I think he's actually talking about the server delaying the
> pre-HELO/EHLO greeting (the server's 220 greeting).  It's new to
> sendmail 8.13.x, and it's called "greet_pause".
> What you want to do, is anywhere after your "access_db" declaration in
> the mc file, put:
> FEATURE(`greet_pause', `30000')dnl
> The 30000 is in milliseconds, so that's a 30 second delay.  Note that
> there are some side effects if you go higher than 28 seconds (verizon
> does "call backs" when accepting email from you, and if they don't get
> a valid response in 28 seconds, they give up and reject your message).
> Also, you can put entries in your access_db that look like this:
> # 220 GreetPause (miliseconds)
> #
> GreetPause:127.0.0      0
> GreetPause:128.114.125  0
> GreetPause:128.114      3000
> GreetPause:169.233      15000
> GreetPause:             30000
> These set aside other delays based upon the connecting host.  0 means
> "disable the delay".
> On Feb 11, 2005, at 14:54, Alex Neuman van der Hans wrote:
>> I don't think that's what he means. It's an option in newer sendmail
>> versions (8.13 I think) that lets you insert a delay between the HELO
>> from
>> the client and the OK from the server.
>> -----Original Message-----
>> From: MailScanner mailing list [mailto:MAILSCANNER at JISCMAIL.AC.UK] On
>> Behalf
>> Of Mark Campbell
>> Sent: Friday, February 11, 2005 5:47 PM
>> Subject: Re: OT Sendmail configuration question
>> Is this what you're looking for?
>> During an SMTP conversation, a client introduces itself to a server
>> using
>> the HELO or EHLO command. The standard does not specify what should be
>> said
>> here, and many Windows clients in fact use a "bogus"
>> name: for instance, the domain name of the destination server.
>> Nevertheless, it may sometimes be useful to check the argument to
>> as many SPAM programs use bogus arguments in a consistent manner.
>> In a very helpful e-mail, a sendmail maintainer explained to me how
>> this
>> could be done. The trick is to use delayed macro expansion with the $s
>> macro. As the sendmail manual explains, $s is a transient macro: at
>> startup,
>> when sendmail reads its configuration file, it contains the name of
>> the host
>> on which sendmail runs, but during an SMTP conversation, it expands
>> into the
>> hostname supplied by the remote client as the argument to HELO/EHLO. By
>> writing $&s, it is possible to delay the expansion of this macro, so
>> it is
>> expanded only when it is needed; e.g., during Local_check_rcpt.
>> Consequently, my sendmail.mc file contains a local rule set similar to
>> the
>> following (note that Local_check_rcpt, if exists, is automatically
>> called by
>> sendmail at the appropriate stage of processing the envelope):
>> SLocal_check_rcpt
>> R$*                     $: $&s
>> Rbogus.domain           $#error $: 550 Spam Forbidden\ ($&s)
>> R$*                     $@ OK
>> REF: http://www.vttoth.com/heloehlo.htm
>> Mark
>> Mark Campbell
>> --
>> IT Convergence OS Administrator <mcampbell at itconvergence.com>
>> -----Original Message-----
>> From: MailScanner mailing list [mailto:MAILSCANNER at JISCMAIL.AC.UK] On
>> Behalf
>> Of Jim Dickenson
>> Sent: Friday, February 11, 2005 4:48 PM
>> Subject: OT Sendmail configuration question
>> Some time ago there was talk on this list about using a relatively new
>> option in sendmail. As I recall there is some option that allows one to
>> delay the response to a helo or ehlo line. The theory was that spammers
>> could not afford to wait when sending messages and they would not wait
>> for
>> the delay time.
>> Can someone remind me what the command was.
>> I tried to search the archive but not knowing exactly what I am
>> searching
>> for I did not find the past messages.
>> Thanks,
>> --
>> Jim Dickenson
>> mailto:dickenson at cfmc.com
>> CfMC
>> http://www.cfmc.com/

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