[ZendTo] {SPAM?} Re: Issues with sending to external users

[Jules]

On 16/01/2017 09:35, Mike Brudenell wrote:
> On 13 January 2017 at 16:24, Jules <Jules at zend.to 
> <mailto:Jules at zend.to>> wrote:
>
>     And as you were sending via IPv6, and utoronto.ca
>     <http://utoronto.ca>'s SPF record does not contain *any* IPv6
>     statements at all, then Google will block all IPv6 mail traffic
>     from utoronto.ca <http://utoronto.ca> (regardless of whether it
>     comes from your ZendTo server or your university's central
>     outgoing mail servers).
>
>
> Not quite… The utoronto.ca <http://utoronto.ca> SPF record ends with 
> "~all" rather than "-all". This indicates only a "softfail" for 
> unlisted hosts that, according to the RFC, means
>
>     A "softfail" result is a weak statement by the publishing ADMD
>     that the host is probably not authorized.  It has not published a
>     stronger, more definitive policy that results in a "fail".
>
That's what it should mean.
Google don't accept IPv6 mail unless you have a specific "ip6:" 
statement in your SPF record, even if you have "~all" or "?all" as well.
>
>
>     If utoronto.ca <http://utoronto.ca> has any IPv6 network in place
>     (which they appear to, as you could get to Google via IPv6), then
>     they really should add an IPv6 statement to their SPF record. Or
>     else no-one is going to want to receive any IPv6 mail they send.
>
>
> It could be that, like ours here, their mail gateways aren't yet IPv6 
> capable in which case the SPF record would be OK (although I'd have 
> hoped their Firewall would have blocked other hosts from sending email 
> out).
Indeed! Maybe their IPv4 firewall does, but not their IPv6 one?
> Also I /think/ we're still only assuming the sending domain is 
> utoronto.ca <http://utoronto.ca>: I don't recall seeing an 
> unobfuscated set of details.
>
> But there's certainly quite a few things in this area Brian needs to 
> investigate!
>
> Cheers,
> Mike B-)
>
> -- 
> Systems Administrator & Change Manager
> IT Services, University of York, Heslington, York YO10 5DD, UK
> Tel: +44-(0)1904-323811
>
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>
>
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Jules

-- 
Julian Field MEng MBCS CITP CEng

'When I read Shakespeare I am struck with wonder
  That such trivial people should muse and thunder
  In such lovely language.' - D.H. Lawrence

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