[Pkg-exim4-users] exim4, gmail and 550-5.7.1

[Marc Haber]

On Wed, Dec 16, 2015 at 05:33:19PM -0500, Robert Steinmetz wrote:
> Marc Haber wrote:
> >On Mon, Dec 14, 2015 at 04:22:00PM -0600, Robert Steinmetz AIA wrote:
> >>I solved it with the postfix server by setting up a list of domains
> >>to be to ipv4 only. That works well and is easy to add more domains
> >>as I discover them
> >The correct way to fix this would be to tell your ISP to fix their
> >IPv6, not by turning it off.
> 
> Unfortunately I have two ISPs at different sites and they both
> exhibit the same problem. As for having them fix it I don't have
> much hope. They have told me to use their smtp servers, which I have
> set up for my users but there are other limitations on their servers which make
> that less than optimal.

Using their SMTP servers is probably the best guess. Running a mail
server on a regular dial-up has become quite hard in the last years.

> >>I did find this web page:
> >>
> >>https://github.com/Exim/exim/wiki/How-to-force-IPv4-connections-for-specific-domains-if-IPv6-is-enabled
> >>
> >>
> >>But I'm not sure how to implement it. I can certainly add a Router
> >>and Transport to the appropriate directory, but where should the
> >>domain list go under conf.d?
> >Domainlists are a rather common element of exim configuration, so
> >chances are high that there is already a domainlist in the default
> >configuration. This proves to be true:
> >
> >[3/500]mh at swivel:~$ grep -lr domainlist /etc/exim4/conf.d/
> >/etc/exim4/conf.d/main/01_exim4-config_listmacrosdefs
> >[4/501]mh at swivel:~$
> >
> >and neatly answers your question that a domainlist needs to be in the
> >"main" part of configuration.
> 
> Great. I did grep the main configuration files and the only domain
> lists I found were:
> 
> root at thelma:/etc/exim4/conf.d/main# grep domainlist *
> 01_exim4-config_listmacrosdefs:domainlist local_domains = MAIN_LOCAL_DOMAINS
> 01_exim4-config_listmacrosdefs:domainlist relay_to_domains = MAIN_RELAY_TO_DOMAINS

Yes, that's exactly what I said and what you quoted.

> >Feel free to open a wishlist bug against exim4-config, I think it
> >might be helpful to offer this mechanismn in the package, offering a
> >file containing a list of target domains that are delivered via IPv4
> >only.
> >
> >Greetings
> >Marc
> >
> Based on the github page I found
> 
> I propose adding a new files in main
> 
> 05_ipv4_force_domains
> 
> Containing:
> 
> domainlist ipv4_force_domains = \
>  gmail.com : \
>  googlemail.com : \
>  virgin.net : \
>  linkedin.com : \
>  virginmedia.com
> 
> 
> Greping router for remote_smtp
> 
> I get
> 
> 100_exim4-config_domain_literal:  transport = remote_smtp
> 150_exim4-config_hubbed_hosts:  transport = remote_smtp
> 200_exim4-config_primary:  transport = remote_smtp
> 200_exim4-config_primary:  transport = remote_smtp
> 200_exim4-config_primary:  transport = remote_smtp_smarthost
> 500_exim4-config_hubuser:  transport = remote_smtp_smarthost

Did you also bother reading the code and trying to understand waht it
does?

> So I propose adding a new file to router called
> 
> 050_exim4_config_ipv4_only.
> 
> Containing
> 
> ipv4_only:
>  driver = dnslookup
>  domains = +ipv4_force_domains
>  transport = ipv4_smtp
>  ignore_target_hosts = <; 0::0/0|

A better name fitting in the nomenclature would be dnslookup_ipv4only,
placed directly before the primary routers in the 200_file, for example
190_exim4-config_dnslookup_ipv4only

> Finally adding a file in transports
> 
> 50_exim4_config_ipv4_only_transport:
> 
> I'm a little puzzled by the one in the example.
> 
> ipv4_smtp:
>  driver = smtp
>  dkim domain = mydomain.co.uk
>  dkim_selector = x
>  dkim_private_key = /usr/exim/dkim.private.key
>  dkim_canon = relaxed
>  interface = <my.v4.ip.address>|

I'd call that remote_smtp_ipv4only, and
50_exim4-config_remote_smtp_ipv45only.

If you want the maintainers to consider this change, you need to file
a bug report, probably with severity wishlist, against the
exim4-config package.

> Why can't I simply use the existing smtp remote_smtp transport with
> the some relatively simple edits? This example contains a directive
> that limits it to using ipv4 by  specifying the interface using an
> ipv4 address. Seems like somewhere should be a directive like
> disable_ipv6 = true or dns_ipv4_lookup = *

That would turn off IPv6 completely. We have 2015, turning off IPv6
these days is a bad idea. You really need to pester your ISPs to
provide you with working IPv6 connectivity.

> I also wonder if these dkim statements conflict with the rest of the
> basic debian configuration.

I cannot say anything about that.

Greetings
Marc

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Marc Haber         | "I don't trust Computers. They | Mailadresse im Header
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