These are issues I've spent only the minimum amount of time on lately, yet they demand resolution. The MrxSmb errors followed me when I took the PCI Gigabit card (DLink) out of my old PC and transferred it to my "new" one. After finding there was still a problem I switched to the onboard Intel 100Mbps NIC and everything is fine. Since we experienced this issue with a variety of NICs, some onboard and some external, I can only conclude that the (presumed) bugs in NIC drivers that lead to these problems are relatively common. An analogy from way back when that I recall, is when certain low-end 3D graphics cards, most notably those made by S3, typically had problems on Windows systems of the era when a large number of icons were displayed. What I've found overall from our experiences is that Intel hardware consistently has less problems than other manufacturers. One of our suppliers of PC hardware in the past consistently buys their boards from a prominent Asian manufacturer (one of the largest in the world) but which uses mainly AMD CPUs and third party chipsets. These tend to cause more problems long term. This particular PC was one of those and has proved very niggling to make work at times. Our present hardware supplier, Cyclone, has standardised on Intel boards and although their graphics chipsets may not be anything to write home about they are consistently solid performers. So my next act will be to get a PCIe gigabit Intel card for this machine, although they cost rather more than the Dlink did.
The DNSAPI errors are more perplexing. Last time this happened it was because the two DNS servers had different reverse lookup zone configs. This time as far as I can tell they are both the same. There has been an ongoing issue with stale reverse lookup records that I have not been able to solve to date, which seems to be related to this problem. However I haven't been able to find out anything about it so far from Microsoft.
