I reported:
> Within the last month or so I've been having trouble copying large
> files to remote servers e.g. sources. The cp process hangs for
> many minutes and eventually ends in 'mount rpc error'.
Thanks to a hint from Erik ("... an mss problem of some sort"), I've
managed to make the problem go away, by doing
echo mtu 1496 >/net/ipifc/1/ctl
I hope to come back to this when I have more time, because I don't
like not understanding why this works. As nobody else has said they
have the same trouble, there may be something amiss in my adsl gateway.