One-Way VPN on Two Netscreens

Hello all,

I am having a slight problem with a couple of our firewall/VPN setups
and decided to turn here for perhaps a little insight.

We have two Netscreens, a ns5XP and a ns25.
To explain configuration easier, here is a couple of snips from config file:

set interface "trust" zone "Trust"
set interface "untrust" zone "Untrust"
set interface trust ip 172.24.248.1/28
set interface trust nat
set interface untrust ip 216.212.XXX.XXX/29
set interface untrust route
...
set address "Trust" "B Subnet" 172.24.248.0 255.255.255.0
set address "Untrust" "A Subnet" 172.25.248.0 255.255.255.0
...
set ike gateway "A_GW" address 69.17.XXX.XXX Main outgoing-interface
"untrust" preshare "XXXXXXXXXXXXX" proposal "XXXXXXXX"
...
set vpn "A_VPN" gateway "A_GW" no-replay tunnel idletime 0 proposal "XXXXXXXXX"
...
set policy id 7 name "A_VPN_Policy" from "Trust" to "Untrust"  "B
Subnet" "A Subnet" "ANY" tunnel vpn "A_VPN" id 10 pair-policy 2
set policy id 2 name "A_VPN_Policy" from "Untrust" to "Trust"  "A
Subnet" "B Subnet" "ANY" tunnel vpn "A_VPN" id 10 pair-policy 7

Other ns has corresponding settings.  I have verified syntax and
addresses are correct on both boxes.


Now this setup has worked without flaw for over a year and the only
recent change was from a cidr /28 to a /24 on "B Subnet".  Both
firewalls have been updated to reflect this change and the VPN works
one way.  Office B can communicate with Internet but not Office A. 
Office A can communicate back and forth to Office B.

Example from Office A to Office B:
ping 172.24.248.2

Pinging 172.24.248.2 with 32 bytes of data:

Reply from 172.24.248.2: bytes=32 time=65ms TTL=125
Reply from 172.24.248.2: bytes=32 time=63ms TTL=125
Reply from 172.24.248.2: bytes=32 time=62ms TTL=125
Reply from 172.24.248.2: bytes=32 time=64ms TTL=125

Ping statistics for 172.24.248.2:
   Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
   Minimum = 62ms, Maximum =  65ms, Average =  63ms

Example from Office B to Office A:
ping 172.25.248.2

Pinging 172.25.248.2 with 32 bytes of data:

Request timed out.
Request timed out.
Request timed out.
Request timed out.

Ping statistics for 172.25.248.2:
   Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
Approximate round trip times in milli-seconds:
   Minimum = 0ms, Maximum =  0ms, Average =  0ms

Both addresses are valid and can be pinged from Office A.

Does anyone have any ideas that could help me out a little?  More info
is available on request.

Thanks,
Mark Owen