[wplug-bsd] Dumb question: "no route to host" but why?

[Brandon Kuczenski]

I am configuring a system running FreeBSD 5.3 to act as a NAT gateway.  It 
receives its real-world IP address over dhcp on interface xl1 and acts as 
a dhcp server to the internal network on interface xl0.

After startup, I can talk to the outside world but when I try to ping a 
destination that should lie on the internal network I get "no route to 
host."

Relevant network config in /etc/rc.conf:

network_interfaces="lo0 xl0 xl1"
ifconfig_xl1="DHCP"
ifconfig_xl0="inet 192.168.1.2 netmask 255.255.255.0"



output of 'netstat -rn' (IPv4 only):
Routing tables

Internet:
Destination        Gateway            Flags    Refs      Use  Netif Expire
default            128.2.56.1         UGS         0      210    xl1
127.0.0.1          127.0.0.1          UH          1       10    lo0
128.2.56/22        link#2             UC          0        0    xl1    500
128.2.56.1         08:00:7f:0a:00:57  UHLW        1        0    xl1   1702
128.2.57.58        127.0.0.1          UGHS        0        0    lo0
192.168.1          link#1             UC          0        0    xl0    495
192.168.1.1        00:13:10:19:67:58  UHLW        0        1    xl0   1780
192.168.1.255      ff:ff:ff:ff:ff:ff  UHLWb       0       12    xl0

192.168.1.1 is the dsl/wireless router with which I am trying to 
communicate.  But pinging, I get:

$ ping 192.168.1.1
PING 192.168.1.1 (192.168.1.1): 56 data bytes
ping: sendto: no route to host

If I try to add an explicit route:
# route add -net 192.168.1.0/24 192.168.1.1
route: writing to routing socket: File exists
add net 192.168.1.0: gateway 192.168.1.1: File exists
# route add -net 192.168.1.0/24 192.168.1.2
route: writing to routing socket: File exists
add net 192.168.1.0: gateway 192.168.1.2: File exists

I have basically the exact same setup at home running FreeBSD 4.11 -- 
except the real-world routing is static -- and it works fine.  The 
handbook looks like it's telling me to do what I've already done.  Am I 
missing something dumb?

Thanks in advance,
Brandon