一面:1.url解析详解?好好背;三次握手除了交换ack和syn还交换了哪些东西;四次握手中间的能不能换成一次(可以,在被动方没有数据要发送的时候); 2.访问一个ip没有加端口时具体的情况;3.mysql语句 select a.username, c.nums from user a inner join (select count(tid) as nums, uid from thread group by uid order nums desc) c where a.uid = c.uid limit 10 ...