附：一些常用的过滤条件表达式(这些条件都是我瞎写的)：
ip.addr == 192.168.5.1 and !ssdp and !dns ip.addr == 192.168.2.11 and tcp.port == 3306 and !ssl tcp.port == 80 and ip.dst == 192.168.5.5 and ip.src == 192.168.2.100 tcp.dstport == 80 or tcp.srcport == 80 http.request.method=="GET" http.request.method=="POST" ip.src==192.168.5.5 and http udp.port == 53 dns or ssdp