Re: [Dnsmasq-discuss] Wildcard / catch all Mail eXchanger (MX)

2021-05-09 Thread Matus UHLAR - fantomas via Dnsmasq-discuss

On 08.05.21 22:44, Mark wrote:

Thanks for the suggestion Petr - have put a DNAT rule in place - does the
job. :)


at least until one of your clients start complaining that you are hijacking
their SMTP connections, which may lead to legal issues.


On Sat, 8 May 2021 at 06:33, Petr Menšík  wrote:

I don't think there exists way to do what you requested using dnsmasq.

However, it might work to DNAT rule outgoing SMTP connections to your
smarthost, moving this decision from DNS to IP firewall/NAT. Could be
done only on some gateway of course.

But I think your users would not like such redirection, I think blocking
outgoing ports and requesting manual configuration from clients might be
more acceptable. Just my 2 cents.



On 5/7/21 4:05 PM, Mark wrote:
> I know there are MX related configuration options which can be used in
> dnsmasq.conf (mx-host, mx-target, selfmx and localmx) - however, none of
> them appear to be able to deliver the specific functionality I'm looking
> for...here's what I'm trying to do...
>
> I have an internal network that is using dnsmasq for name resolution and
> some (not all) hosts are using it for DHCP.
>
> I would like dnsmasq to deliver a single MX record back to MX queries
> from
> hosts on my internal network no matter what mail domain is being included
> in their MX query - i.e. a 'wildcard MX' (which I'll point to my SMTP
> smarthost).
>
> The description of the 'mx-host' option in dnsmasq's man page makes
> reference to this type of requirement ("for directing mail from systems
> on
> a LAN to a central server") - however, dnsmasq still appears to need to
> be
> configured to provide responses only for specifically mail domains
> ("hostname") MX requests.
>
> Essentially, I believe I want to specify a wildcard as the "hostname"
> (really "mail domain").
>
> I wondered if it's possible to deliver this functionality with the
> current
> dnsmasq?
>
> Appreciate any insights you're able to share.


--
Matus UHLAR - fantomas, uh...@fantomas.sk ; http://www.fantomas.sk/
Warning: I wish NOT to receive e-mail advertising to this address.
Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu.
Save the whales. Collect the whole set.

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Re: [Dnsmasq-discuss] Wildcard / catch all Mail eXchanger (MX)

2021-05-09 Thread Mark
On Mon, 10 May 2021 at 01:17, Matus UHLAR - fantomas via Dnsmasq-discuss <
dnsmasq-discuss@lists.thekelleys.org.uk> wrote:

> On 08.05.21 22:44, Mark wrote:
> >Thanks for the suggestion Petr - have put a DNAT rule in place - does the
> >job. :)
>
> at least until one of your clients start complaining that you are hijacking
> their SMTP connections, which may lead to legal issues.
>

Thanks for your message - not directly related to my question, but I
appreciate the assumptions, opinion and opportunity to discuss.

Given the non-deterministic nature of SMTP (there's no guarantee of how or
when a message will be delivered), I'm surprised that unsigned, unencrypted
messages have any legal standing whatsoever - however, legal systems are a
law to themselves (so to speak).

So, I agree, some jurisdictions *may* determine intercepting (or
"hijacking") SMTP connections has legal implications (although I personally
think this would be a stretch)..however, I'm 100% certain my 'clients'
won't start complaining (never have, never will!). ;)

Thanks again, Mark


>
> >On Sat, 8 May 2021 at 06:33, Petr Menšík  wrote:
> >> I don't think there exists way to do what you requested using dnsmasq.
> >>
> >> However, it might work to DNAT rule outgoing SMTP connections to your
> >> smarthost, moving this decision from DNS to IP firewall/NAT. Could be
> >> done only on some gateway of course.
> >>
> >> But I think your users would not like such redirection, I think blocking
> >> outgoing ports and requesting manual configuration from clients might be
> >> more acceptable. Just my 2 cents.
>
> >> On 5/7/21 4:05 PM, Mark wrote:
> >> > I know there are MX related configuration options which can be used in
> >> > dnsmasq.conf (mx-host, mx-target, selfmx and localmx) - however, none
> of
> >> > them appear to be able to deliver the specific functionality I'm
> looking
> >> > for...here's what I'm trying to do...
> >> >
> >> > I have an internal network that is using dnsmasq for name resolution
> and
> >> > some (not all) hosts are using it for DHCP.
> >> >
> >> > I would like dnsmasq to deliver a single MX record back to MX queries
> >> > from
> >> > hosts on my internal network no matter what mail domain is being
> included
> >> > in their MX query - i.e. a 'wildcard MX' (which I'll point to my SMTP
> >> > smarthost).
> >> >
> >> > The description of the 'mx-host' option in dnsmasq's man page makes
> >> > reference to this type of requirement ("for directing mail from
> systems
> >> > on
> >> > a LAN to a central server") - however, dnsmasq still appears to need
> to
> >> > be
> >> > configured to provide responses only for specifically mail domains
> >> > ("hostname") MX requests.
> >> >
> >> > Essentially, I believe I want to specify a wildcard as the "hostname"
> >> > (really "mail domain").
> >> >
> >> > I wondered if it's possible to deliver this functionality with the
> >> > current
> >> > dnsmasq?
> >> >
> >> > Appreciate any insights you're able to share.
>
> --
> Matus UHLAR - fantomas, uh...@fantomas.sk ; http://www.fantomas.sk/
> Warning: I wish NOT to receive e-mail advertising to this address.
> Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu.
> Save the whales. Collect the whole set.
>
> ___
> Dnsmasq-discuss mailing list
> Dnsmasq-discuss@lists.thekelleys.org.uk
> https://lists.thekelleys.org.uk/cgi-bin/mailman/listinfo/dnsmasq-discuss
>
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