預設：Intra-Interface Communications disabled，不允許進出同介面的路由
Intra-Interface Communications Enable 指令：
same-security-traffic permit intra-interface
http://www.cisco.com/en/US/products/ps6120/products_tech_note09186a0080734db7.shtml
增加以下兩行，route inside 封包，不做 NAT.
1. ACL
access-list route-inside extended permit ip 192.168.0.0 255.255.0.0 192.168.0.0 255.255.0.0
2. NAT 0 (不做 NAT)
nat (inside) 0 access-list route-inside
