a missing rule / incomplete routing

[lejeczek <peljasz@yahoo.co.uk>]

dear experts

I'm looking for ideas/suggestion why the following does not work

there is a:
* box A - 172.17.166.199 --  then there is 172./8 net -- box 
B - 172.25.12.101 (phys0), 192.168.2.100 (phys1) -- and one 
more net behind 192.168.2.100

a 192.168.2.81 from behind box B can ping172.17.166.199
but not the other way around, box A cannot get to box B's 
phys1 but it does get to phys0

I can control box A but have no control over the nets 
between it and box B's phys0
I can control box B

I thought my route rules on box B are complete, box A is a 
winbox
I though box B' firewall is ready
but I obviously miss something

there is no masquerading for phys0 nor phys1 one box B

any ideas/thoughts? greatly appreciated
thanks
P.