At 11:35 PM 1/28/2007 -0500, Stuart D. Gathman wrote:
On Sun, 28 Jan 2007, Don Lee wrote:
> There is a large and growing number of mailservers "out there" that
> try to resolve the HELO name, and some do rDNS on the IP and
> ensure that it matches the HELO.
There is no need to do the rDNS if the HELO name resolves to the IP. It
is a (minor) waste of bandwidth and is unfair to those of us with
broken ISP monopolies. I suppose I am a broken record on the topic.
Sendmail seems to do the rDNS lookup by default, so I don't know what to do
about the bandwidth issue.
When a connection request first comes in, the milter gets a call that looks
like:
def connect(self, IPname, ctype, hostaddr):
''' (self, 'dyn68.net71.example.com', AF_INET, ('216.183.71.68', 4720) )
(self, 'ip6.example.com', AF_INET6, ('3ffe:80e8:d8:::::1', 4720,
1, 0))
As you say, the "IPname" is often not very useful. It is assigned by the
network owner, and station operators within their network have little
control over it. The HELO name *is* under the station operator's control,
and is much more useful for identifying and assigning reputation to the
party responsible for the transmission.
Does anyone know how to turn off the rDNS lookup in Sendmail? Is an rDNS
lookup by default common in other mail programs?
-- Dave
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