Re: MTA (corrected)

[Joe <joe@jretrading.com>]

On Mon, 5 Jul 2021 16:55:44 +0200
Vincent Lefevre <vincent@vinc17.net> wrote:

> On 2021-07-05 10:32:27 -0400, Polyna-Maude Racicot-Summerside wrote:
> > > What is this 162.213.253.79 IP address?  
> > 
> > The IP address 162.213.253.79 is the dedicated IP I rent from
> > Namecheap.  
> 
> OK.
> 
> >  Can you control its reverse?  
> > >  
> > Good question, I'll need to go back read a bit on networking and DNS
> > management.  
> > > Is cyrania.com a domain that you own?  
> > Yes, I own cyrania.com and polynamaude.com (the domain name used
> > for the email I am sending). I know the SMTP server respond to the
> > name CYRANIA.COM (HELO) but is relaying mail for polynamaude.com
> > too.  
> 
> It seems that you already set up the reverse for 162.213.253.79 since
> it is cyrania.com (your domain).
> 
> You may want to add 162.213.253.79 to the cyrania.com IP addresses,
> but if cyrania.com is used as a www host and 162.213.253.79 shoud
> not be used for this purpose, this is not OK.
> 
> In general, it is better to have a specific FQDN for each IP address.
> For instance, 162.213.253.79 would have nodename.cyrania.com as the
> reverse and nodename.cyrania.com would resolve to 162.213.253.79,
> where nodename is the name obtained with the "uname -n" command.
> 

It's not a big issue. My public FQDN and PTR have no relationship at
all with any email domain I use, and I've never had mail refused for
that reason, over more than fifteen years. I also use a single HELO, and
that only matches one domain. Again, no problem with the other domains.

My mail server doesn't check for matching anywhere, only that a sending
IP address has complementary PTR and FQDN, and that the FQDN and HELO
are resolvable in public DNS, and I think that's a common setup.

-- 
Joe