On 2024-10-16 at 09:52:43 UTC-0400 (Wed, 16 Oct 2024 14:52:43 +0100)
Dominic Preston via Postfix-users <lzq...@gmail.com>
is rumored to have said:
On Wed, 16 Oct 2024 at 14:30, Bill Cole via Postfix-users <
postfix-users@postfix.org> wrote:
[....]
However, multi-second delays at connect time are perfectly normal and
intentional in many cases. For example, Postfix's postscreen
component will
pause for 7 seconds at connect time in the middle of the intro banner
for
IPs that are not in its cache of non-spambot clients.
Understood, although when clicking "Send" on a tiny email, it's
something
of an irritant to be looking at the sending bar for several seconds
before
it actually sends.
If what you're seeing is a postscreen delay on your own mail server, you
can exempt your client IP's with a postscreen_access_list
Is there any way to disable PTR record lookups for a given set of
IPv4/IPv6
addresses?
On your own mail server, the canonical mechanism to short-circuit
rDNS
lookups is to add entries in the hosts file for the IPs needing the
faster
resolution, assuming that you have your system resolver set to use
files
first (in /etc/nsswitch.conf)
Unfortunately modifying the hosts file isn't going to work, I use IPv6
with
temporary addressing, so I'd need to add billions of addresses to the
hosts
file, or use a solution with a subnet mask.
Then the solution would be a local resolver on the mail server which is
authoritative for that address range. It need not be authoritative as
far as the world at large is concerned, just so that the mail server
doesn't try a recursive resolution that ends up waiting for your
connection provider. As Victor suggested, Unbound is probably the best
tool for a mail server's local resolution, as it is much simpler than
BIND. It may be possible to use dnsmasq for this, but it is really not
designed for this sort of task, as it is primarily just a forwarder, not
a resolver.
--
Bill Cole
b...@scconsult.com or billc...@apache.org
(AKA @grumpybozo@toad.social and many *@billmail.scconsult.com
addresses)
Not Currently Available For Hire
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