Emails is the center of life for almost every business in this world. When email is down businesses cannot communicate. There is loss of productivity which could lead to dollars lost, which in the end is not good.

Daily monitoring of Exchange involves many aspects of the environment and the surrounding infrastructure.  Simply turning on monitoring will not get you very far. First question you should ask yourself is “What do I need to monitor?” Not knowing what to look out for could inundate you with alerts which is not going to be helpful for you.

One of the first places to look at when troubleshooting mail slowness or other email issues is the network. Therefore, it is a good idea to monitor some basic network counters on the Exchange Servers. These counters will help guide you to determine where the root cause of the issue is.

 

Network Counters

The following tables displays acceptable thresholds and information about common network counters.

 

Counter

Description

Threshold

Network Interface(*)\Packets Outbound Errors

Indicates the number of outbound packets that couldn't be transmitted because of errors.

Should be 0 at all times.

TCPv6\Connection Failures

Shows the number of TCP connections for which the current state is either ESTABLISHED or CLOSE-WAIT. The number of TCP connections that can be established is constrained by the size of the nonpaged pool. When the nonpaged pool is depleted, no new connections can be established.

Not applicable

TCPv4\Connections Reset

Shows the number of times TCP connections have made a direct transition to the CLOSED state from either the ESTABLISHED state or the CLOSE-WAIT state.

An increasing number of resets or a consistently increasing rate of resets can indicate a bandwidth shortage.

TCPv6\Connections Reset

Shows the number of times TCP connections have made a direct transition to the CLOSED state from either the ESTABLISHED state or the CLOSE-WAIT state.

An increasing number of resets or a consistently increasing rate of resets can indicate a bandwidth shortage.

 

 


Monitoring Beyond the Exchange Environment


When your monitoring exchange not only are you monitoring for performance but you also want to monitor outside factors such as network, active directory, and any external connections such as mobile device management. All these external factors will affect the health of your Exchange environment.

In order to run Exchange, you need a network, yes routers and switches can impact exchange. As the exchange admin you don’t need to be aware of every single network event but a simple alert of a network outage or blip can be helpful. Sometimes all it takes is a slight blip in the network and it could have could affect your Exchange DAG by causing databases to fail over.

If you are not responsible for the network, then I would suggest you coordinate with your network team on what notifications you should be made aware in terms of network outages. Some key items to be informed or notified of are:

  • Planned outages between datacenters
  • Planned outages for network equipment
  • Network equipment upgrades and or changes that would affect the subnet your exchange servers reside on
  • Unplanned outages of network equipment and between datacenters
  • If your servers are virtualized, you should be informed of any host changes and/or virtual switch changes
  • Planned or unplanned DNS server changes because DNS issues can be a real nightmare

Preventing Bigger Headaches

Exchange Monitoring is a headache and can be time consuming but if you know what you are looking for and have the right tools in hand it is not so bad.  If the Exchange DAG is properly designed a network blip or outage should not take down your email for you company, this is the whole point of having an Exchange DAG( high availability design). What you may get is a help desk calls when users see that their outlook has disconnected briefly. Being informed of potential network outages can help you prepare in advance if you need to manually switch active copies of databases or when you need to do mailbox migrations. A network that is congested or having outages can cause mailbox migrations to fail, cause outlook clients to disconnect and even impact the speed of email delivery. Knowing ahead of time allows you to be prepared and have less headaches.