Running Vibe 3.4

I was troubleshooting different problem on our mail server when I discovered that every 5 minutes the vibe server is connecting to the mail server. It doesn't appear to be sending anything to it, just looks like it is testing connectivity.
One of the connections from the mail server log: (These repeat every 5minutes) [server names replaced]
2014-09-18T15:12:15.663Z,MailServer,08D1A1535BE0885E,0,172 .22.1.16:25,172.22.1.50:43870,+,,
2014-09-18T15:12:15.663Z,MailServer,08D1A1535BE0885E,1,172 .22.1.16:25,172.22.1.50:43870,*,SMTPSubmit SMTPAcceptAnySender SMTPAcceptAuthoritativeDomainSender AcceptRoutingHeaders,Set Session Permissions
2014-09-18T15:12:15.663Z,MailServer,08D1A1535BE0885E,2,172 .22.1.16:25,172.22.1.50:43870,>,"220 MailServer.our.domain Microsoft ESMTP MAIL Service ready at Thu, 18 Sep 2014 10:12:15 -0500",
2014-09-18T15:12:15.663Z,MailServer,08D1A1535BE0885E,3,172 .22.1.16:25,172.22.1.50:43870,<,EHLO vibeserver.our.domain,
2014-09-18T15:12:15.663Z,MailServer,08D1A1535BE0885E,4,172 .22.1.16:25,172.22.1.50:43870,>,250-MailServer.our.domain Hello [172.22.1.50],
2014-09-18T15:12:15.663Z,MailServer,08D1A1535BE0885E,5,172 .22.1.16:25,172.22.1.50:43870,>,250-SIZE 10485760,
2014-09-18T15:12:15.663Z,MailServer,08D1A1535BE0885E,6,172 .22.1.16:25,172.22.1.50:43870,>,250-PIPELINING,
2014-09-18T15:12:15.663Z,MailServer,08D1A1535BE0885E,7,172 .22.1.16:25,172.22.1.50:43870,>,250-DSN,
2014-09-18T15:12:15.663Z,MailServer,08D1A1535BE0885E,8,172 .22.1.16:25,172.22.1.50:43870,>,250-ENHANCEDSTATUSCODES,
2014-09-18T15:12:15.663Z,MailServer,08D1A1535BE0885E,9,172 .22.1.16:25,172.22.1.50:43870,>,250-AUTH,
2014-09-18T15:12:15.663Z,MailServer,08D1A1535BE0885E,10,17 2.22.1.16:25,172.22.1.50:43870,>,250-8BITMIME,
2014-09-18T15:12:15.663Z,MailServer,08D1A1535BE0885E,11,17 2.22.1.16:25,172.22.1.50:43870,>,250-BINARYMIME,
2014-09-18T15:12:15.663Z,MailServer,08D1A1535BE0885E,12,17 2.22.1.16:25,172.22.1.50:43870,>,250 CHUNKING,
2014-09-18T15:12:15.663Z,MailServer,08D1A1535BE0885E,13,17 2.22.1.16:25,172.22.1.50:43870,<,QUIT,
2014-09-18T15:12:15.663Z,MailServer,08D1A1535BE0885E,14,17 2.22.1.16:25,172.22.1.50:43870,>,221 2.0.0 Service closing transmission channel,
2014-09-18T15:12:15.663Z,MailServer,08D1A1535BE0885E,15,17 2.22.1.16:25,172.22.1.50:43870,-,,Local

Is this normal?

-Mike