Get rid of the special "default" value for dumpon's -g parameter.

[markj]

Summary

Instead, treat the absence of -g to mean that the default route is to be
selected. (And if there is no default route, dump directly to the
server.) The netdump client always attempts to ARP the server directly
anyway, so it doesn't hurt to always configure a gateway.

[cem]

sbin/dumpon/dumpon.8

142–143

I think being a little more redundant and mirroring the sentence structure might make it more clear. Something like:

If the
.Fl g
option is not specified and the system has a default route configured, the default route is used as the netdump gateway.
.Pp
If the
.Fl g
option is not specified and the system has
.Em no
default route configured, the
.Xr netdumpd 8
.Ar server
is assumed to be on the same link as the
.Ar client .

I don't feel strongly about it, though.

I'd drop the clause about packets being directly transmitted to the server; that follows logically from 'same link' and 'no gateaway' for anyone familiar with IP networking, and for anyone who isn't familiar, the clause is kind of meaningless anyway.

[markj]

• Address feedback.

[markj]

sbin/dumpon/dumpon.8

142–143

I didn't copy the suggestion exactly, but it's pretty similar.

[cem]

Looks great to me, thanks!