>    3) I'm also getting occasional "ie0: DMA underflow" messages on the
> 3/4xx. Haven't seen it on the 3/50s and 3/60s, so it may be in the ie
> driver. This appears to be harmless, since the data always seems to be
> intact. It shows up when transfering very large (dozens of megabytes)
> files via FTP.

This sounds as though data may well be being lost at the ie driver
level, but the TCP layer is doing its job of detecting the loss and
arranging for retransmission.  Such problems are not entirely harmless,
since the retransmissions reduce throughput and services which do not
use TCP may be impacted more significantly than those that do.

If it happens when the 3/4xx is receiving (rather than sending) large
files, flooding the 3/4xx with large ping packets from another system
might make the problem more visible and reproducible.