請教各位有關跨網段互連的問題

以下是我們公司的架構圖
[url=http://www.go2upload.com/view/2/dcc021.html][img]http://www.go2upload.com/thumb/dcc021.gif[/img][/url]
A,B2點是透過網達IP VPN連線,A點3個SWITCH串接是D-LINK DES-1024D
B的網路是透過網達的IP VPN連線到A點透過FTTB上網

Router的設定如下

Multiple Subnet
介面位址/192.168.200.1
子網路遮罩/ 255.255.255.0
WAN 1 : X.X.X.X/ NAT模式

路由表設定
目的位址 /192.168.200.0
子網路遮罩 / 255.255.255.0
閘道位址/192.168.123.254

192.168.200.X的user連回192.168.123.X的伺服都很正常
現在有個狀況是192.168.123.X的user連不到192.168.200.X的user
但是有時候PING -t一陣子後就通了,但是隔天又TIMED OUT了
從Client端Tracert 192.168.200.100 的結果如下
Target Name: N/A
IP: 192.168.200.100
1 1 ms 0 ms 1 ms 1 ms 1 ms 1 ms 1 ms 0 ms 5 ms 0 ms [192.168.123.1]
2 * * * * * * * * * N/A [-]
3 * * * * * * * * * N/A [-]
4 * * * * * * * * * N/A [-]
5 * * * * * * * * * N/A [-]
6 * * * * * * * * * N/A [-]
Destination not reached in 35 hops
Destination not reached in 35 hops

從192.168.123.1這台ROUTER TRACERT 192.168.200.100的結果如下
raceroute to 192.168.200.100 (192.168.200.100), 30 hops max, 40 byte packets from 192.168.123.1

From 192.168.123.1
To hop 1 : IP = 192.168.123.254 round-trip min/avg/max = 107.574/119.062/129.604 ms
To hop 2 : IP = 192.168.1.1 round-trip min/avg/max = 164.751/174.054/182.105 ms
To hop 3 : IP = 192.168.200.100 round-trip min/avg/max = 107.682/153.292/181.656 ms

Traceroute complete
想請教各位朋友問題出在那呢?:eye: