I have a customer having some DNS issues. They have done some research regarding some DNS timeout errors they saw with Verizon's sender verify looking up their MX records. What they have discovered is their current DNS service has a 1% failure/timeout rate. They are exploring other vendors (UltraDNS for one), but need an estimate of the number of DNS queries for accurate pricing to put together a ROI argument for the switch. I have no IDEA if this can be determined, but what is a good estimate of the number of DNS queries generated from sending an email? I know that it may differ from ISP to ISP, but they just need a rough number for pricing purposes. If you also happen to know how many DNS requests make it to the root server (rather than a cached proxy out on the net), that would be great. -Dennis