Now they are the 6 servers of Hotmail with Timed out.
This goes of badly to worse.
New.

mx2.hotmail.com. - 65.54.190.50 [Could not connect: Could not connect to mail server (timed out).]
mx3.hotmail.com. - 64.4.50.179 [Could not connect: Could not connect to mail server (timed out).]
mx3.hotmail.com. - 65.54.253.99 [Could not connect: Could not connect to mail server (timed out).]
mx4.hotmail.com. - 65.54.190.179 [Could not connect: Could not connect to mail server (timed out).]
mx4.hotmail.com. - 65.54.253.230 [Could not connect: Could not connect to mail server (timed out).]
mx1.hotmail.com. - 64.4.50.50 [Could not connect: Could not connect to mail server (timed out).]



<http://www.dnsreport.com/tools/[EMAIL PROTECTED]>http://www.dnsreport.com/tools/[EMAIL PROTECTED]




There are not 6 hotmail MXs timing out. There are only 4 MX hostnames, 1-4, each with 4 IPs, for a total of 16 IPs (and I bet those IPs are really load balancers rather than single machines)

;; ANSWER SECTION:
hotmail.com.            72      IN      MX      5 mx1.hotmail.com.
hotmail.com.            72      IN      MX      5 mx2.hotmail.com.
hotmail.com.            72      IN      MX      5 mx3.hotmail.com.
hotmail.com.            72      IN      MX      5 mx4.hotmail.com.

;; ADDITIONAL SECTION:
mx1.hotmail.com.        1142    IN      A       65.54.252.99
mx1.hotmail.com.        1142    IN      A       64.4.50.50
mx1.hotmail.com.        1142    IN      A       64.4.50.99
mx1.hotmail.com.        1142    IN      A       65.54.166.99

mx2.hotmail.com.        1142    IN      A       65.54.252.230
mx2.hotmail.com.        1142    IN      A       65.54.166.230
mx2.hotmail.com.        1142    IN      A       65.54.190.7
mx2.hotmail.com.        1142    IN      A       65.54.190.50

mx3.hotmail.com.        1142    IN      A       65.54.253.99
mx3.hotmail.com.        1142    IN      A       64.4.50.179
mx3.hotmail.com.        1142    IN      A       64.4.50.239
mx3.hotmail.com.        1142    IN      A       65.54.167.5

mx4.hotmail.com.        1142    IN      A       65.54.190.230
mx4.hotmail.com.        1142    IN      A       65.54.253.230
mx4.hotmail.com.        1142    IN      A       65.54.167.230
mx4.hotmail.com.        1142    IN      A       65.54.190.179

The above setup, which is not original MS/hotmail approach (which used only one IP), is copied from AOL, which has been setup like that for years. Another example of MS following, not leading.

Our report is per MX, not per IP:

operation timed out (total: 8251)
       201   mx3.hotmail.com
       169   mx4.hotmail.com
        97   mx1.hotmail.com
        92   mx2.hotmail.com

... where our SMTP timeout is set to 60 seconds (between SMTP commands/responses).

But mail is still going through to hotmail, eventually, at least with postfix's implementation of the MX algorithm and with BIND as postfix's DNS:

Host/Domain Summary: Message Delivery (top 30)
 sent cnt  bytes   defers   avg dly  max dly  host/domain
 -------- -------  -------  -------  -------  -----------
   1514     9735k     246     2.7 m   16.1 h  aol.com
   1180     5880k     198    56.0 s   16.5 h  bellsouth.net
   1103     6117k    2409    34.7 m   16.5 h  cox.net
   1088     7301k     123    56.7 s   16.2 h  comcast.net
    726     5585k       0    30.7 s   10.9 m  earthlink.net
    671     3196k      80    44.9 s   15.6 h  sbcglobal.net
    361     2383k       0     2.6 m   15.0 m  hotmail.com  <<<<<<<<<<<<<<<
    357     1798k       0    42.5 s   10.8 m  mindspring.com
    340     1954k       0     1.8 m   23.9 m  msn.com

Note that the 2.6 minutes "average delivery delay" means that even when your MTA gets a connection to hotmail, hotmail is very slow in accepting your data, which isn't a problem Imail since I think Imail will wait almost indefinitely for SMTP progress (vs our 60 seconds setting). Imail's patience does mean that Imail can have a LOT of SMTP sessions in progress, perhaps to DoS levels. Being able to define your MTA's SMTP/D timeouts means you can protect it from being overloaded with slow-to-dead SMTP sessions.

If you aren't getting anything through to hotmail, then the hotmail problems are compounded by problems with your MTA's inefficiencies (or other local problems) in working the MX algorithm (or you are blacklisted). Another problem is that the NS used by Imail (eg, MS DNS) is not rotating or otherwise varying evenly the order of MX and A record-sets, so Imail's A queries are not getting answers distributed evenly across the full set of 16 IPs.

Len

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