Had an interesting outbound email isse in Exchange 2003. I don't see as many of these anymore since Exchange 2007 and 2010 have come out. Email to a couple of domains outbound wouldn't work.
I went into the DNS manager and then to the properties and found the forwarders were using opendns.org for content filtering.
After discussing it, the customer wanted to keep those IPs where they were. I went into the Exchange manager and the SMTP properties under protocol. Instead of using the DNS forwarders I had to specify Exchange to only use a specific DNS IP instead and I put in the Verizon servers. Email then flowed as it should, and I didn't have to change their content filtering IPs.
I'm on lots of shows this week. Besides the All Tech Radio show, I did the Jeff Kropf show yesterday as usual, and I'm doing the Think Out Loud show on OPB tomorrow. This weekend I'm doing some sort of live question and answer at the Washington County Fair. Should be fun.