NFS through routers & turning on UDP checksums in NFS?

[Robert Richards]

Is NFS mounting safe through routers? A traditional objection has been
that most NFS implementations don't use checksums on their UDP datagrams,
so that packets damaged by routers would cause undetected corrupt data for
users.

Is there some standard way of turning on UDP checksums in the common NFS
implementations (eg SunOS, Ultrix, etc), both client and server?