回帖：这个是日志，谁能帮忙分析一下：
#Software: Microsoft Exchange Server
#Version: 15.0.0.0
#Log-type: Transport Connectivity Log
#Date: 2017-10-25T13:07:44.561Z
#Fields: date-time,session,source,Destination,direction,description
2017-10-25T13:07:15.560Z,08D516A12C1B584C,SMTP,qq.com,+,DnsConnectorDelivery c551c911-901c-4cae-956f-2459859e5bbb;QueueLength=TQ=1;RN=1;.
2017-10-25T13:07:15.607Z,08D516A12C1B584D,SMTP,qq.com,+,DnsConnectorDelivery c551c911-901c-4cae-956f-2459859e5bbb;QueueLength=TQ=1;RN=1;.
2017-10-25T13:07:15.623Z,08D516A12C1B584D,SMTP,qq.com,>,"mx3.qq.com[240e:ff:f040:28::f, 183.57.48.35], mx2.qq.com[240e:ff:f040:28::f, 14.17.41.170, 59.37.97.124], mx1.qq.com[183.57.48.35, 240e:ff:f040:28::f]"
2017-10-25T13:07:15.623Z,08D516A12C1B584C,SMTP,qq.com,>,"mx3.qq.com[240e:ff:f040:28::f, 183.57.48.35], mx2.qq.com[240e:ff:f040:28::f, 14.17.41.170, 59.37.97.124], mx1.qq.com[183.57.48.35, 240e:ff:f040:28::f]"
2017-10-25T13:07:15.623Z,08D516A12C1B584C,SMTP,qq.com,-,Messages: 0 Bytes: 0 (Pending)
2017-10-25T13:07:15.623Z,08D516A12C1B584D,SMTP,qq.com,>,Failed connection to 240e:ff:f040:28::f:25 (NetworkUnreachable:00002743)
2017-10-25T13:07:15.623Z,08D516A12C1B584D,SMTP,qq.com,-,Messages: 0 Bytes: 0 (Attempting next target)
2017-10-25T13:07:15.623Z,08D516A12C1B584E,SMTP,qq.com,*,Session Failover; previous session id = 08D516A12C1B584D; reason = SocketError
2017-10-25T13:07:15.623Z,08D516A12C1B584E,SMTP,qq.com,+,DnsConnectorDelivery c551c911-901c-4cae-956f-2459859e5bbb;QueueLength=TQ=0;RN=1;.
2017-10-25T13:07:36.654Z,08D516A12C1B584E,SMTP,qq.com,>,Failed connection to 183.57.48.35:25 (TimedOut:0000274C)
2017-10-25T13:07:36.654Z,08D516A12C1B584E,SMTP,qq.com,-,Messages: 0 Bytes: 0 (Attempting next target)
2017-10-25T13:07:36.654Z,08D516A12C1B584F,SMTP,qq.com,*,Session Failover; previous session id = 08D516A12C1B584E; reason = SocketError
2017-10-25T13:07:36.654Z,08D516A12C1B584F,SMTP,qq.com,+,DnsConnectorDelivery c551c911-901c-4cae-956f-2459859e5bbb;QueueLength=TQ=0;RN=1;.
2017-10-25T13:07:36.654Z,08D516A12C1B584F,SMTP,qq.com,>,Failed connection to 240e:ff:f040:28::f:25 (NetworkUnreachable:00002743)
2017-10-25T13:07:36.654Z,08D516A12C1B584F,SMTP,qq.com,-,Messages: 0 Bytes: 0 (Attempting next target)
2017-10-25T13:07:36.654Z,08D516A12C1B5850,SMTP,qq.com,*,Session Failover; previous session id = 08D516A12C1B584F; reason = SocketError
2017-10-25T13:07:36.654Z,08D516A12C1B5850,SMTP,qq.com,+,DnsConnectorDelivery c551c911-901c-4cae-956f-2459859e5bbb;QueueLength=TQ=0;RN=1;.
2017-10-25T13:07:57.670Z,08D516A12C1B5850,SMTP,qq.com,>,Failed connection to 14.17.41.170:25 (TimedOut:0000274C)
2017-10-25T13:07:57.670Z,08D516A12C1B5850,SMTP,qq.com,-,Messages: 0 Bytes: 0 (Attempting next target)
2017-10-25T13:07:57.670Z,08D516A12C1B5851,SMTP,qq.com,*,Session Failover; previous session id = 08D516A12C1B5850; reason = SocketError
2017-10-25T13:07:57.670Z,08D516A12C1B5851,SMTP,qq.com,+,DnsConnectorDelivery c551c911-901c-4cae-956f-2459859e5bbb;QueueLength=TQ=0;RN=1;.
2017-10-25T13:08:18.717Z,08D516A12C1B5851,SMTP,qq.com,>,Failed connection to 59.37.97.124:25 (TimedOut:0000274C)
2017-10-25T13:08:18.717Z,08D516A12C1B5851,SMTP,qq.com,-,Messages: 0 Bytes: 0 (Attempting next target)
2017-10-25T13:08:18.717Z,08D516A12C1B5852,SMTP,qq.com,*,Session Failover; previous session id = 08D516A12C1B5851; reason = SocketError
2017-10-25T13:08:18.717Z,08D516A12C1B5852,SMTP,qq.com,+,DnsConnectorDelivery c551c911-901c-4cae-956f-2459859e5bbb;QueueLength=TQ=0;RN=1;.
2017-10-25T13:08:39.733Z,08D516A12C1B5852,SMTP,qq.com,>,Failed connection to 183.57.48.35:25 (TimedOut:0000274C)