I'm  running on a system compiled from (according to the date on last.allsrc)
July 13th sources.  I've been having some trouble in the last week with route.
route change -host somehost.cc.iastate.edu -interface
will consistently panic my computer.  
As far as I can tell, any properly(?) formatted route change will
do the same.

% route -v add -host somehost.cc.iastate.edu -interface
u:inet 129.186.140.###; RTM_ADD: Add Route: len 92, pid:0, seq 1, errno 0, flags:<UP,HOST,STATIC>
locks: inits:
sockaddrs: <DST>
 somehost
writing to routing socket: Invalid argument
add host somehost.cc.iastate.edu: Invalid argument  

I have read the route man pages over and over, and have managed to become
very confused.  This problem began when I brought my i386 -current NetBSD
box home, and added it to a working network consisting of 2 linux boxes.
We run PPP to campus, and while I can always (so far) reach the gateway
box, I can only reach the other Linux box for the first hour or
so after I reboot, then its entry in netstat -nr will be:

Destination	Gateway		Flags	Refs	Use	Interface
129.186.140.###	129.186.140.### UGHD	0	6	ed0

(Destination and Gateway are the same.)
(this is after I pinged it, and received no response.)
The only way to actually get a route to somehost for the first hour 
is a gross hack in /etc/rc:

echo Configuring local loopback interface lo0...
ifconfig lo0 inet 127.0.0.1
echo Configuring routes...
route add $HOSTIP 127.0.0.1
[ -n "$MYGATE" ] && {
        echo Default gateway is $MYGATE...
        route add default $MYGATE
}
[ "$NETKLUDGE" = "yes" ] && {
        echo 'Kludging routing tables (be very afraid)...'
        ping -c 1 129.186.140.###
        route delete 129.186.0.0
}

I'm not sure what information about my system would be helpful, but
I'll answer any questions to the best of my ability.

The complete output of the pertinent section of netstat -nr is

root@solstice# netstat -nr
Routing tables

Internet:
Destination      Gateway            Flags     Refs     Use  Interface
default          129.186.140.107    UGS         4     6920  ed0
127.0.0.1        127.0.0.1          UH          2      126  lo0
129.186.140.###  129.186.140.###    UGHD        0        6  ed0
129.186.140.107  0:20:af:15:aa:d    UHL         1        0  ed0
129.186.140.113  127.0.0.1          UGHS        1       28  lo0

Tracy J. Di Marco                 gendalia@iastate.edu
System Administrator                          294-2279
Geographic Information Systems              218 Durham
Support and Research Facility    Iowa State University