dhclient on solaris 10

[Ted Lemon]

That's very weird.   I don't *think* this would be related, but have  
you disabled the built-in solaris DHCP client?   Also, with that  
subnet mask, your IP address and the router's IP address are actually  
on the same subnet, so it's not an error.   My only conjecture here is  
that your subnet mask is being set incorrectly on the interface for  
some reason.   Can you do an ifconfig on the interface after  
configuring with dhclient and see if the subnet mask matches what  
you're seeing in your lease?