Routing to internet addresses ending with 255

[Manolis Kiagias]

I had this weird problem today, and I would like to know what caused it:

I have two home servers, on different locations, on two ADSL lines using 
dynamic DNS. One is running Debian, the other FreeBSD 7.0-RELEASE.

I usually ssh from one to the other. Today, the debian server had a 
public (internet) IP ending in 255. The FreeBSD 7.0 system refused to 
communicate with it. Another 6.3 system had no problem. The 6.3 and 7.0 
system have identical adsl routers.

Trying a traceroute from 7.0, it would seem the debian system was one 
hop away, which is of course incorrect.

I understand that x.x.x.255 is ethernet's broadcast address. However 6.3 
had no problem connecting to it, while 7.0 would not. Has something 
changed in FreeBSD, is this the intended behaviour or a bug? 
Furthermore, is it valid for my ISP to assign me an address ending in 255?

The workaround was of course to ssh from another system, telnet into the 
router and reboot it so it gets another address. I would still like to 
know if there is any other solution.