David Sharpe wrote:
> Recently (Mid-January 2008) Hotmail has developed some intermittent
> delivery problem with email being
> sent through our server.
>
> * A new message to a hotmail address is discarded by Hotmail and never
> shown to the user
> * A reply to a message - to a hotmail address - is delivered reliably
> * All email from Hotmail to our server is delivered reliably
>
> Mail logs show mail is queued correctly on the Hotmail servers in all
> cases - any suggestions as to why
> mail is suddenly being silently dropped?
Their filters are dumb. You can get most email through by making the
messages look like replies by adding fake References/In-Reply-To
headers. Before your normal dnslookup router add a router like this:
dnslookup_hotmail:
driver = dnslookup
condition = ${if match_domain{${lookup
dnsdb{>:defer_never,mxh=$domain}{$value}{}}}{*.hotmail.com}{true}{false}}
transport = remote_smtp
headers_remove = User-Agent
headers_add = ${if !def:h_References:{References:
<BAY000-000000000000000000000000000@???>\n}}\
${if !def:h_In-Reply-To:{In-Reply-To:
<BAY000-000000000000000000000000000@???>\n}}
ignore_target_hosts = 0.0.0.0 : 127.0.0.0/8
no_more
The "headers_remove = User-Agent" line is something entirely different
that tends to help. You'll find many references on the web to hotmail
blocking certain messages that contain Thunderbird in the User-Agent
header, but allowing through messages that are exactly the same, but
without the User-Agent header. I tested this myself a while back and it
was true.
This information comes with no guarantee. For all I know hotmail may
turn around one day and start blocking messages with fake References
headers. They're not at the moment though.
MikeC2
