EXCHANGE_DELIVERY_TIME shows absurd values
On Windows 2003/Exchange 2003, the check for EXCHANGE_DELIVERY_TIME will often show absurd values. On Exchange 2007, it shows reasonable values but the check will still show warning or critical very frequently.
This is a bug in the performance counter \MSExchangeIS Mailbox(_Total)\Average Delivery Time
According to the documenation, this counter is the average delivery time for the last ten messages delivered in Exchange. However, it actually counts the total delivery time for the last ten messages (and apparently sometimes even more than that).
As far as I know, this problem has been fixed in Exchange 2007, and the counter returns reasonable values.
In addition, the warning and critical thresholds in TNTMonitoring are set too low.
If you are monitoring an Exchange 2003 server, ignore this check altogether.
If you are monitoring Exchange 2007, you may want to edit the file exchange.service.config (in the C:\Program Files\The NetTech\The NetTech Monitoring Script directory). Edit the line that starts with &EXCHANGE_DELIVERY_TIME& Change the warning and critical thresholds to 2 minutes and 5 minutes, respectively: -w 120000 -c 300000
The next release of TNTMonitoring will include this change.