I've got 2 Exchange servers running HUB, CAS and MBX with DAG, 2 servers being Active Directory, 1 witness server and 1 TMG server. They are split evenly between 3 Hyper-V servers:

Server 1

  • Exchange 1
  • Ad 1
  • Witness (I should move it to 3rd)

Server 2

  • Exchange 2
  • Ad 2

Server 3

  • TMG

Before that they were all on one server. This is test environment that went live due to total failure at our mail provider.

The problem is ping to Exchange 1 or Exchange 2 or DAG IP occasionally is very high or even loosing packets, dropping RDP connections etc. Ping between AD1 and AD2 or TMG is fine. Just everything that comes/goes to/from change1/Exchange2 is high (normally it's 1-2ms (while AD1 to AD2 is less then 1ms) and it likes to jump to 1000ms or loosing packets from time to time. It's very intermittent, it even sometimes reported problems with DAG or witness file share because of network issue but the problems even occurred on one Hyper-V server (between AD1,Exchange1,Witness). The network is very simple - one VLAN for that network and everything else on those Hyper-V machines is separated into other VLAN's.

Is it normal that the ping is higher then 1ms in LAN network? Also DAG IP seems to be attached to only one server at the time. When that server goes down it switches that IP to other server. How to diagnose this very basic network configuration?


Seems like I've missed that the Exchange servers for some reason have LAN as Legacy Network Adapter in Hyper-V. After changing to Normal Network Card in Hyper-V everything works. Something to be aware of and to check when things go weird :-)

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