Tunnel works on 10.10.1.0-10.10.2.0, and not works on 172.16.1.0-172.16.2.0

[Rashid N. Achilov]

FreeBSD 8.1-RELEASE. Occured a strange thing.

Take two boxes with 8.1. Do these:
On #1
ifconfig gif create
ifconfig gif0 tunnel AAA.AAA.AAA.AAA BBB.BBB.BBB.BBB
ifconfig gif0 inet 10.10.1.254 10.10.2.254 netmask 255.255.255.255

On #2
ifconfig gif create
ifconfig gif0 tunnel BBB.BBB.BBB.BBB AAA.AAA.AAA.AAA
ifconfig gif0 inet 10.10.2.254 10.10.1.254 netmask 255.255.255.255

Next, do ping 10.10.2.254 from box #1. Worked!

Now do these:
On #1
ifconfig gif create
ifconfig gif0 tunnel AAA.AAA.AAA.AAA BBB.BBB.BBB.BBB
ifconfig gif0 inet 172.16.1.254 172.16.2.254 netmask 255.255.255.255

On #2
ifconfig gif create
ifconfig gif0 tunnel BBB.BBB.BBB.BBB AAA.AAA.AAA.AAA
ifconfig gif0 inet 172.16.2.254 172.16.1.254 netmask 255.255.255.255

Next, do ping 172.16.2.254 from box #1. Not worked :-O

Replace boxes onto 7.3-STABLE and re-do last sample (with 172.16). Worked!

Why? Is there any problems in 8.1?
-- 
   With Best Regards.
   Rashid N. Achilov (RNA1-RIPE), JID: citycat4 at jabber.infos.ru
   OOO "ACK" telecommunications administrator, e-mail: achilov-rn [at] askd.ru
   PGP: 83 CD E2 A7 37 4A D5 81 D6 D6 52 BF C9 2F 85 AF 97 BE CB 0A