Hi,
All receiving mails(external only) are getting delayed in our organization but sending mails are working properly. for ex: im sending one mail from gmail at 09.00 am it is reaching imsva server at 09.00.02 am and for scanning and some other process it is taking 3 to 4 seconds after the scan it has to reach exchange server.after passing the scan it is taking 5 to 10 minutes to deliver that mail to exchange server.
Smtp relay server = Imsva trend micro.
All mails are passing through Hardware load balancer (Radware)
gmail->smtp relay server(imsva)->hardware load balancer(Radware)->exchange server 2010