Adding multicast route fails

["Evan Champion" <evanc@concer.to>]

From /etc/netstart:

# route -n add -net 224.0.0.0 -interface default
writing to routing socket: Network is unreachable
add net 224.0.0.0: gateway default: Network is unreachable

If I replace this with:

# route -n add -net 224.0.0.0 -interface `cat /etc/mygate`
add net 224.0.0.0: gateway 206.47.37.1

the route gets added as I would expect.

My routing table before trying to add the multicast route is:

Destination        Gateway            Flags     Refs     Use    Mtu
Interface
default            206.47.37.1        UGS         0        1      -
127/8              127.0.0.1          UGRS        0        0      -
127.0.0.1          127.0.0.1          UH          0        4      -
192.168.1/24       link#2             UC          0        0      -
192.168.1.1        127.0.0.1          UGHS        0        0      -
192.168.1.2        0:e0:18:90:19:bc   UHL         0        2      -
206.47.37/24       link#1             UC          0        0      -
206.47.37.1        0:60:47:c6:6f:8    UHL         0        1      -

I kind of suspect that it has something to do with my kernel
configuration, because this works on the generic kernel.  Perhaps it is
because I don't have any of the COMPAT_* (but I don't think I should
need them for route to work!)?

My kernel config (minus device section) is:

machine         i386            # architecture, used by config; REQUIRED
option          I586_CPU

maxusers        32              # estimated number of users

option          TIMEZONE=0      # time zone to adjust RTC time by
option          DST=0           # daylight savings time used by RTC
option          NTP             # hooks supporting the Network Time
Protocol

option          SWAPPAGER       # paging; REQUIRED
option          DEVPAGER        # mmap() of devices

option          DIAGNOSTIC      # internal consistency checks
option          KTRACE          # system call tracing, a la ktrace(1)

option          SYSVMSG         # System V-like message queues
option          SYSVSEM         # System V-like semaphores
option          SYSVSHM         # System V-like memory sharing
#option         SHMMAXPGS=1024  # 1024 pages is the default

option          FFS             # UFS

option          TCP_SACK        # Selective Acknowledgements for TCP
option          TCP_FACK        # Forward Acknowledgements for TCP

#option         MSDOSFS         # MS-DOS file system
option          FDESC           # /dev/fd
option          FIFO            # FIFOs; RECOMMENDED

option          GATEWAY         # packet forwarding
#option         MROUTING
option          INET            # IP + ICMP + TCP + UDP
#option         IPSEC           # IPsec
option          IPFILTER        # IP packet filter for security
option          IPFILTER_LOG    # use /dev/ipl to log IPF

pseudo-device   loop    2       # network loopback
pseudo-device   bpfilter 8      # packet filter
#pseudo-device  enc     1       # encryption device

pseudo-device   pty     64      # pseudo-terminals
pseudo-device   ksyms   1       # kernel symbols device
pseudo-device   random  1


Any ideas?

Evan