Sendmail: x-authentication-warning ... claimed to be Local IP

S

sidney2017

Hi,

after having installed sendmail 8.17.1 on FreeBSD 13, the following warning message appears in the mail header on the recipient side:

Domainname sm-mta [46633]: 1BSNHHd3046633: x-authentication-warning: Domainname.tld: Host dslb-047-123-052-076.XXX.044.pools.tcom-ip.de [X.X.X.X] claimed to be [192.168.0.30]

So far I only knew a similar message, which can be avoided with entries in /etc/mail/trusted-users for example:
X-Authentication-Warning: host: user set sender to other using -f ...
Click to expand...

Does anyone of you know how I can prevent this entry in the header of the emails I send with sendmail?

Thanks in advance and kind regards
Sidney2017
 
Hi,

thanks for your hint to PICKY_HELO_CHECK!

How can one fix the sending host HELO greeting?

Is it possible to DISABLE that PICKY_HELO_CHECK by editing the .mc-file and generating a new sendmail.cf?
Or will I have to recompile sendmail?

Here is explained how one can ENABLE by help of the sendmail.mc file:

3.4.42
Ordinarily, sendmail doesn’t care what the calling host calls itself. All sendmail cares about is that this name is the canonical name of a machine. If you care whether the HELO hostname matches the real hostname of the calling machine, you can add a line such as the following to your Build m4 file: APPENDDEF(`confENVDEF´, `-DPICKY_HELO_CHECK´)

With PICKY_HELO_CHECK defined, a mismatch (other than the local machine calling itself localhost) will cause the following warning to be logged: Host realname claimed to be heloname

Note that this check is ordinarily turned off because a large number of hosts on the Internet use a name that is different from their canonical name.*
Click to expand...

I installed sendmail 8.17.1 with "pkg install sendmail".

Will I have to remove that package before compiling sendmail from the ports without PICKY HELO CHECK?

Thanks and kind regards
Sidney2017
 
Thanks, but is it recommendable to delete the sendmail-package I installed with "pkg install" before building the sendmail version with the port?

Thanks and best regards
Sidney2017
 
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