I meant a strange problem.The toplogy is below:I have set up two IPSEC VPN , "106.0" to "53.0" is strange: I can't ping 172.29.53.13 from "106.0",but can ping other IPs. Meantime, 172.29.53.13 can't ping any IPs in "106.0". "21.0" to "53.0" is okHer...