Is learning network, and what they put on OpenWrt iptables is deleted, the router into a pure Linux host, oneself write a software to realize NAT, I considered this software only the TCP and UDP protocol, the work done by the IP address to replace, and then to recalculate the IP and TCP or UDP checksum, measured and Telnet ping domain name is successful, but can't open web pages, sometimes can load part title and content, can't think why, hope everybody cues what reason can cause this kind of situation, I good step by step screen