For the past two weeks we have taken an unusual project: Find out why certain messages get deferred or delayed at random times to random recipients. While this task is something that we perform routinely through our support portal, my staff has taken a lot of abuse at the hands of something that is really not an ExchangeDefender issue or something we are capable of addressing.

Last week we have introduced a layer of monitoring service to ExchangeDefender that has been collecting data on failures our clients servers are experiencing. This data is being plotted for each IP address we hand off mail to. So far we have been able to identify users that have:

Inadequate Internet connections (bandwidth or reliability)

Inadequate Firewalls or routers (connections time out, get deferred or dropped randomly)

Configuration problems (lack of space, lack of resources)

We have made several adjustments to the way we deliver mail for the clients that have frequent or persistent delay problems. In each researched case we have been able to isolate the problem to the recipients servers or network not cooperating. We have attempted to replicate the scenario with servers / addresses that are not on the same ranges or networks to eliminate the possibility of network/routing causing a problem.

We are continuing our work on this because no user should be frustrated with the delays in their message delivery. If there is anything we can do to determine if these issues are persistent enough to recommend additional resources or spotlight problems that the admins or MSPs are not aware of, I’m glad to do so. It is in all our users best interest.

Sincerely,
Vlad Mazek, MCSE
CEO, Own Web Now Corp

P.S. There is only one legitimate reason for mail delays: Senders IP address is on a commercial RBL like SpamCop or SpamHaus. These messages are delayed intentionally and whitelisting does not affect the performance, they will get delayed. This behavior has been in place for a long time with ExchangeDefender and is not set to change: Senders on SpamCop and SpamHaus have been confirmed as spammers by independent parties and have not done anything to delist themselves. We can only assume that these resources are not managed and we just cannot trust mail from these hosts, even if you chose to trust the senders from those domains.