Hi,

I've run into the following head scratcher:

I'm seeing different responses to EHLO depending if the client is
connected with IPv4 vs IPv6.

Both DaemonPorts have the same configuration save for the expected
Address, Family, and Name.

I'm at a loss as to where to start looking for this different behavior.

Does anyone have any ideas what to check first?

#[user@REDACTED:~]% nc -4 REDACTED 25
220 REDACTED ESMTP Sendmail 8.15.2/8.15.2; Thu, 25 Mar 2021 17:58:17 GMT
ehlo REDACTED
250-REDACTED Hello REDACTED [REDACTED], pleased to meet you 250-ENHANCEDSTATUSCODES
250-PIPELINING
250-EXPN
250-VERB
250-8BITMIME
250-SIZE
250-DSN
250-ETRN
250-STARTTLS
250-DELIVERBY
250 HELP
rset
250 2.0.0 Reset state
quit
221 2.0.0 REDACTED closing connection

#[user@REDACTED:~]% nc -6 REDACTED 25
220 REDACTED ESMTP Sendmail 8.15.2/8.15.2; Thu, 25 Mar 2021 17:58:35 GMT
ehlo REDACTED
250-REDACTED Hello REDACTED [REDACTED] (may be forged), pleased to meet you
250 ENHANCEDSTATUSCODES
rset
250 2.0.0 Reset state
quit
221 2.0.0 REDACTED closing connection

Aside: I'm also perplexed by the "(may be forged)" in that response.
Both forward and reverse DNS are functioning correctly on the host and
the Internet at large.



--
Grant. . . .
unix || die

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 3/25/21 12:08 PM, Grant Taylor wrote:

I'm seeing different responses to EHLO depending if the client is
connected with IPv4 vs IPv6.

It seems as if adding the `delay_checks' FEATURE may have solved (or at
least worked around) my problem. But I don't understand why.

Aside:  I'm also perplexed by the "(may be forged)" in that response.
Both forward and reverse DNS are functioning correctly on the host and
the Internet at large.

I still don't know what to make of the "(may be forged)" message.



--
Grant. . . .
unix || die

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)