2
Delayed delivery to Office 365 subscribers
Problem reported by Brian Shrift - July 1, 2016 at 2:05 PM
Submitted
We have been receiving a number of reports regarding bounce backs and delayed delivery reports.
Upon looking into the attempted recipient domains we found that a commonality was that they were using Office 365 for their email solution.
 
After reviewing the logs, we are seeing a pattern of timeouts and connection rejections due to meeting a threshold of connections open to O365 servers.
 
Log:
 
[2016.06.30] 12:24:03 [25173] Delivery started for client1@domainA.com at 12:24:03 PM
[2016.06.30] 12:24:15 [25173] Skipping spam checks: User authenticated
[2016.06.30] 12:24:18 [25173] Starting local delivery to client2@domainA.com
[2016.06.30] 12:24:18 [25173] Delivery for client1@domainA.com to client2@domainA.com has completed (Delivered) Filter: None
[2016.06.30] 12:24:18 [25173] End delivery to client2@domainA.com
[2016.06.30] 12:24:18 [25173] Sending remote mail for client1@domainA.com
[2016.06.30] 12:24:18 [25173] Initiating connection to 207.46.163.215
[2016.06.30] 12:24:18 [25173] Connecting to 207.46.163.215:25 (Id: 1)
[2016.06.30] 12:24:18 [25173] Binding to local IP 192.168.100.40:0 (Id: 1)
[2016.06.30] 12:24:18 [25173] Connection to 207.46.163.215:25 from 192.168.100.40:52466 succeeded (Id: 1)
[2016.06.30] 12:26:18 [25173] The smtp session has timed out.
[2016.06.30] 12:36:19 [25173] Sending remote mail for client1@domainA.com
[2016.06.30] 12:36:19 [25173] Initiating connection to 207.46.163.247
[2016.06.30] 12:36:19 [25173] Connecting to 207.46.163.247:25 (Id: 1)
[2016.06.30] 12:36:19 [25173] Binding to local IP 192.168.100.40:0 (Id: 1)
[2016.06.30] 12:36:19 [25173] Connection to 207.46.163.247:25 from 192.168.100.40:52657 succeeded (Id: 1)
[2016.06.30] 12:38:19 [25173] The smtp session has timed out.
[2016.06.30] 12:38:19 [25173] Delay notification email written to 236425276.eml
[2016.06.30] 12:48:22 [25173] Sending remote mail for client1@domainA.com
[2016.06.30] 12:48:22 [25173] Initiating connection to 207.46.163.247
[2016.06.30] 12:48:22 [25173] Connecting to 207.46.163.247:25 (Id: 1)
[2016.06.30] 12:48:22 [25173] Binding to local IP 192.168.100.40:0 (Id: 1)
[2016.06.30] 12:48:22 [25173] Connection to 207.46.163.247:25 from 192.168.100.40:52866 succeeded (Id: 1)
[2016.06.30] 12:50:22 [25173] The smtp session has timed out.
[2016.06.30] 13:00:23 [25173] Sending remote mail for client1@domainA.com
[2016.06.30] 13:00:24 [25173] Initiating connection to 207.46.163.247
[2016.06.30] 13:00:24 [25173] Connecting to 207.46.163.247:25 (Id: 1)
[2016.06.30] 13:00:24 [25173] Binding to local IP 192.168.100.40:0 (Id: 1)
[2016.06.30] 13:00:24 [25173] Connection to 207.46.163.247:25 from 192.168.100.40:53076 succeeded (Id: 1)
[2016.06.30] 13:02:24 [25173] The smtp session has timed out.
[2016.06.30] 13:02:24 [25173] Initiating connection to 207.46.163.170
[2016.06.30] 13:02:24 [25173] Connecting to 207.46.163.170:25 (Id: 2)
[2016.06.30] 13:02:24 [25173] Binding to local IP 192.168.100.40:0 (Id: 2)
[2016.06.30] 13:02:24 [25173] Connection to 207.46.163.170:25 from 192.168.100.40:53101 succeeded (Id: 2)
[2016.06.30] 13:04:24 [25173] The smtp session has timed out.
[2016.06.30] 13:04:24 [25173] Initiating connection to 207.46.163.138
[2016.06.30] 13:04:24 [25173] Connecting to 207.46.163.138:25 (Id: 3)
[2016.06.30] 13:04:24 [25173] Binding to local IP 192.168.100.40:0 (Id: 3)
[2016.06.30] 13:04:24 [25173] Connection to 207.46.163.138:25 from 192.168.100.40:53147 succeeded (Id: 3)
[2016.06.30] 13:04:24 [25173] RSP: 421 4.3.2 The maximum number of concurrent server connections has exceeded a per-source limit, closing transmission channel (BN1AFFO11FD054.protection.gbl)
[2016.06.30] 13:04:24 [25173] CMD: QUIT
[2016.06.30] 13:34:32 [25173] Sending remote mail for client1@domainA.com
[2016.06.30] 13:34:32 [25173] Initiating connection to 207.46.163.247
[2016.06.30] 13:34:32 [25173] Connecting to 207.46.163.247:25 (Id: 1)
[2016.06.30] 13:34:32 [25173] Binding to local IP 192.168.100.40:0 (Id: 1)
[2016.06.30] 13:34:32 [25173] Connection to 207.46.163.247:25 from 192.168.100.40:53685 succeeded (Id: 1)
[2016.06.30] 13:36:32 [25173] The smtp session has timed out.
[2016.06.30] 13:36:32 [25173] Bounce email written to 236425790.eml
[2016.06.30] 13:36:32 [25173] Delivery for client1@domainA.com to abc@domain.com has completed (Bounced)
[2016.06.30] 13:36:32 [25173] Delivery finished for client1@domainA.com at 1:36:32 PM    [id:236425173]
 
NDRs:
"Subject: Delivery delay notification
 
The server(s) that the message "RE: Email Subject XYZ" is attempting to be
sent to has temporarily delayed the delivery for the following recipient(s):
 
abc@domain.com
 
There will be up to 2 more delivery attempt(s) of this message. Do not
re-send your message until there are no more delivery attempt(s) and the
messages bounces back to you."
_____________________________________________________________
"Subject: Delivery Failure
 
Could not deliver message to the following recipient(s):
 
Failed Recipient: abc@domain.com
Reason: Remote host said: 601 Attempted to send the message to the following
ip's:
                207.46.163.247"
 
 
Has anyone encountered this before? Any solutions or thoughts?

1 Reply

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Bruce Barnes Replied
July 2, 2016 at 12:22 AM
Without more specific information on your SmarterMail server's FQDN, your m the PUBIC IP ADDRESS, and your SmarterMail server's other configuration information, along with the name of the SENDING DOMAIN NAM, thisis,virtually to diagnose further You can PM the information to me, and I will be glad to give you an analysis of how,the Internet, and other MX servers see your confirmation, which may assist in the resolution of your issues, ir open a,support ticket with SmarterMail. Please remember this is,the 4th of July weekend ib the,United States, and support will be very limited until any backlog of issues are,resolved during the short work-week ahead.
Bruce Barnes
ChicagoNetTech Inc

Phone: (224) 444-0169

E-Mail and DNS Security Specialist
Network Security Specialist

Customer Service Portal: https://portal.chicagonettech.com
Website: https://www.ChicagoNetTech.com
Security Blog: http://networkbastion.blogspot.com/

Web and E-Mail Hosting, E-Mail Security and Consulting

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