While working on Sonicwall routers, I found some interesting things. After setting up monitoring of the Sonicwall routers via Cacti, I was able to turn on monitoring of “errors”. As I found errors on the ports, almost every error was due to the port on either the Sonicwall or the switch being set incorrectly.
When looking at the ports, either set both ports to 100Mb full duplex, or set them to auto-negotiate. If the switch is a non-managed switch, then set the Sonicwall to auto-negotiate. If the switch is managed, and you can, set both to 100Mb full [or 1Gb if both ports support it]. Where I have seen this be a big advantage with when your connected to a Cisco switch, if you can lock both ports to the same speed and duplex, you will get no errors and the fastest link.
From what I can tell, the biggest issue is on the 100mb/10mb ports. These are found on TZ100 and TZ200 Sonicwall switches.