[pfx] Trying to limit the number of users per connection and the number of concurrent connections to one domain
Paul Tomblin via Postfix-users <[email protected]> Fri, 26 Jun 2026 14:43:51 -0400
| Newsgroups | gmane.mail.postfix.user |
|---|---|
| Message-ID | <[email protected]> |
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I've got a bunch of Mailman3 mailing lists, but one of them has 500+ users, and about 60 of them are on @rochester.rr.com (RoadRunner, which was Time Warner's broadband system, but now it's part of Spectrum). And RoadRunner has been bouncing all or nearly all the emails because of either too many recipients per connection, or too many simultaneous connections. So what I've done so far is I told Mailman to not limit the number of recipients per connection (max_recipients: 0), and then I configured a new transport in postfix. I put the following in master.cf:
`# For systems that don't like multiple connections:
slow_smtp unix - - n - - smtp
-o syslog_name=postfix-slow
`
Then I set up the transport file:
`# Transport map for connections that don't like high concurrency (like Time F***ing Warner)
rochester.rr.com slow_smtp:rochester.rr.com
`
And then in the mail.cf I've set some configuration for slow_smtp
`# F***ing road runner
slow_smtp_destination_concurrency_limit = 2
slow_smtp_destination_recipient_limit = 5
`
It looks right, and the log indicates that the slow_smtp transport is being used for rochester.rr.com addresses, but right now it's sending the whole 60 of them all in one connection. I thought the configuration I had would send them to 5 recipients at a time, and only make two connections at a time until the backlog was cleared. I don't know what their actual limits are, but I want to be able to get this setup working so I can test it.
--
Paul Tomblin
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<!DOCTYPE html><html><head><title></title></head><body><div>I've got a b=
unch of Mailman3 mailing lists, but one of them has 500+ users, and abou=
t 60 of them are on @rochester.rr.com (RoadRunner, which was Time Warner=
's broadband system, but now it's part of Spectrum). And RoadRunner has =
been bouncing all or nearly all the emails because of either too many re=
cipients per connection, or too many simultaneous connections. So what I=
've done so far is I told Mailman to not limit the number of recipients =
per connection (max_recipients: 0), and then I configured a new transpor=
t in postfix. I put the following in master.cf:</div><pre style=3D"borde=
r-top-width:1px;border-right-width:1px;border-bottom-width:1px;border-le=
ft-width:1px;border-top-style:solid;border-right-style:solid;border-bott=
om-style:solid;border-left-style:solid;border-top-color:rgb(204, 204, 20=
4);border-right-color:rgb(204, 204, 204);border-bottom-color:rgb(204, 20=
4, 204);border-left-color:rgb(204, 204, 204);border-image-source:initial=
;border-image-slice:initial;border-image-width:initial;border-image-outs=
et:initial;border-image-repeat:initial;border-top-left-radius:3px;border=
-top-right-radius:3px;border-bottom-right-radius:3px;border-bottom-left-=
radius:3px;background-image:initial;background-position-x:initial;backgr=
ound-position-y:initial;background-size:initial;background-repeat:initia=
l;background-attachment:initial;background-origin:initial;background-cli=
p:initial;background-color:rgb(246, 246, 246);font-family:menlo, consola=
s, monospace;font-size:90%;margin-top:7px;margin-right:0px;margin-bottom=
:7px;margin-left:0px;padding-top:7px;padding-right:10px;padding-bottom:7=
px;padding-left:10px;white-space-collapse:preserve;text-wrap-mode:wrap;o=
verflow-wrap:break-word;"><code style=3D"border-top-width:1px;border-rig=
ht-width:1px;border-bottom-width:1px;border-left-width:1px;border-top-st=
yle:solid;border-right-style:solid;border-bottom-style:solid;border-left=
-style:solid;border-top-color:rgb(204, 204, 204);border-right-color:rgb(=
204, 204, 204);border-bottom-color:rgb(204, 204, 204);border-left-color:=
rgb(204, 204, 204);border-image-source:initial;border-image-slice:initia=
l;border-image-width:initial;border-image-outset:initial;border-image-re=
peat:initial;border-top-left-radius:3px;border-top-right-radius:3px;bord=
er-bottom-right-radius:3px;border-bottom-left-radius:3px;background-imag=
e:initial;background-position-x:initial;background-position-y:initial;ba=
ckground-size:initial;background-repeat:initial;background-attachment:in=
itial;background-origin:initial;background-clip:initial;background-color=
:rgb(246, 246, 246);font-family:menlo, consolas, monospace;font-size:90%=
;padding-top:1px;padding-right:3px;padding-bottom:1px;padding-left:3px;"=
># For systems that don't like multiple connections:=0Aslow_smtp unix - =
- n - - smtp=0A -o syslog_name=3Dpostfix=
-slow=0A</code></pre><div>Then I set up the transport file:</div><pre st=
yle=3D"border-top-width:1px;border-right-width:1px;border-bottom-width:1=
px;border-left-width:1px;border-top-style:solid;border-right-style:solid=
;border-bottom-style:solid;border-left-style:solid;border-top-color:rgb(=
204, 204, 204);border-right-color:rgb(204, 204, 204);border-bottom-color=
:rgb(204, 204, 204);border-left-color:rgb(204, 204, 204);border-image-so=
urce:initial;border-image-slice:initial;border-image-width:initial;borde=
r-image-outset:initial;border-image-repeat:initial;border-top-left-radiu=
s:3px;border-top-right-radius:3px;border-bottom-right-radius:3px;border-=
bottom-left-radius:3px;background-image:initial;background-position-x:in=
itial;background-position-y:initial;background-size:initial;background-r=
epeat:initial;background-attachment:initial;background-origin:initial;ba=
ckground-clip:initial;background-color:rgb(246, 246, 246);font-family:me=
nlo, consolas, monospace;font-size:90%;margin-top:7px;margin-right:0px;m=
argin-bottom:7px;margin-left:0px;padding-top:7px;padding-right:10px;padd=
ing-bottom:7px;padding-left:10px;white-space-collapse:preserve;text-wrap=
-mode:wrap;overflow-wrap:break-word;"><code style=3D"border-top-width:1p=
x;border-right-width:1px;border-bottom-width:1px;border-left-width:1px;b=
order-top-style:solid;border-right-style:solid;border-bottom-style:solid=
;border-left-style:solid;border-top-color:rgb(204, 204, 204);border-righ=
t-color:rgb(204, 204, 204);border-bottom-color:rgb(204, 204, 204);border=
-left-color:rgb(204, 204, 204);border-image-source:initial;border-image-=
slice:initial;border-image-width:initial;border-image-outset:initial;bor=
der-image-repeat:initial;border-top-left-radius:3px;border-top-right-rad=
ius:3px;border-bottom-right-radius:3px;border-bottom-left-radius:3px;bac=
kground-image:initial;background-position-x:initial;background-position-=
y:initial;background-size:initial;background-repeat:initial;background-a=
ttachment:initial;background-origin:initial;background-clip:initial;back=
ground-color:rgb(246, 246, 246);font-family:menlo, consolas, monospace;f=
ont-size:90%;padding-top:1px;padding-right:3px;padding-bottom:1px;paddin=
g-left:3px;"># Transport map for connections that don't like high concur=
rency (like Time F***ing Warner)=0Arochester.rr.com slow_smtp:rochester.=
rr.com=0A</code></pre><div>And then in the mail.cf I've set some configu=
ration for slow_smtp</div><pre style=3D"border-top-width:1px;border-righ=
t-width:1px;border-bottom-width:1px;border-left-width:1px;border-top-sty=
le:solid;border-right-style:solid;border-bottom-style:solid;border-left-=
style:solid;border-top-color:rgb(204, 204, 204);border-right-color:rgb(2=
04, 204, 204);border-bottom-color:rgb(204, 204, 204);border-left-color:r=
gb(204, 204, 204);border-image-source:initial;border-image-slice:initial=
;border-image-width:initial;border-image-outset:initial;border-image-rep=
eat:initial;border-top-left-radius:3px;border-top-right-radius:3px;borde=
r-bottom-right-radius:3px;border-bottom-left-radius:3px;background-image=
:initial;background-position-x:initial;background-position-y:initial;bac=
kground-size:initial;background-repeat:initial;background-attachment:ini=
tial;background-origin:initial;background-clip:initial;background-color:=
rgb(246, 246, 246);font-family:menlo, consolas, monospace;font-size:90%;=
margin-top:7px;margin-right:0px;margin-bottom:7px;margin-left:0px;paddin=
g-top:7px;padding-right:10px;padding-bottom:7px;padding-left:10px;white-=
space-collapse:preserve;text-wrap-mode:wrap;overflow-wrap:break-word;"><=
code style=3D"border-top-width:1px;border-right-width:1px;border-bottom-=
width:1px;border-left-width:1px;border-top-style:solid;border-right-styl=
e:solid;border-bottom-style:solid;border-left-style:solid;border-top-col=
or:rgb(204, 204, 204);border-right-color:rgb(204, 204, 204);border-botto=
m-color:rgb(204, 204, 204);border-left-color:rgb(204, 204, 204);border-i=
mage-source:initial;border-image-slice:initial;border-image-width:initia=
l;border-image-outset:initial;border-image-repeat:initial;border-top-lef=
t-radius:3px;border-top-right-radius:3px;border-bottom-right-radius:3px;=
border-bottom-left-radius:3px;background-image:initial;background-positi=
on-x:initial;background-position-y:initial;background-size:initial;backg=
round-repeat:initial;background-attachment:initial;background-origin:ini=
tial;background-clip:initial;background-color:rgb(246, 246, 246);font-fa=
mily:menlo, consolas, monospace;font-size:90%;padding-top:1px;padding-ri=
ght:3px;padding-bottom:1px;padding-left:3px;"># F***ing road runner=0Asl=
ow_smtp_destination_concurrency_limit =3D 2=0Aslow_smtp_destination_reci=
pient_limit =3D 5=0A</code></pre><div>It looks right, and the log indica=
tes that the slow_smtp transport is being used for rochester.rr.com addr=
esses, but right now it's sending the whole 60 of them all in one connec=
tion. I thought the configuration I had would send them to 5 recipients =
at a time, and only make two connections at a time until the backlog was=
cleared. I don't know what their actual limits are, but I want to be ab=
le to get this setup working so I can test it.</div><div><br></div><div>=
<br></div><div id=3D"sig164736223"><div class=3D"signature">--</div><div=
class=3D"signature">Paul Tomblin</div><div class=3D"signature"><br></di=
v></div><div><br></div></body></html>
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