这取决于iphdr.saddr
字段。 当它被设置为我自己的地址或随机组播地址时,我可以看到服务器使用syn/ack数据包进行回复。 如果设置为其他ips,服务器没有回复。 如何解释?当我尝试通过原始套接字连接时,为什么tcp服务器不回复syn包?
多播地址的情况下: 13:55:08.242535 IP 240.151.224.61.13579 > localhost.5223: Flags [S], seq 123456, win 4096, length 0 E..([email protected][email protected]$X.. 13:55:14.906511 IP 239.151.224.61.13579 > localhost.5223: Flags [S], seq 123456, win 4096, length 0 E..([email protected][email protected]%X.. 13:55:14.906549 IP localhost.5223 > 239.151.224.61.13579: Flags [S.], seq 3502093187, ack 123457, win 43690, options [mss 65495], length 0 E..,[email protected]@..........=.g5........A
... N ....... 13:55:15.904599 IP localhost.5223> 239.151.224.61.13579:旗[S.],SEQ 3502093187,ACK 123457 ,赢得43690,选项[MSS 65495],长度为0
`
我自己的地址情况: 14:14:22.989225 IP slave1.domain.com.13579 > localhost.5223: Flags [S], seq 123456, win 4096, length 0 E..([email protected]@....P...3... 14:14:22.989236 IP localhost.5223 > slave1.domain.com.13579: Flags [S.], seq 3228604881, ack 123457, win 43690, options [mss 65495], length 0 E..,[email protected]@..........m.g5..p.....A
... A5 ...... 14:14:22.989259 IP slave1.domain.com .13579> localhost.5223:Flags [。],ack 3228604882,win 4096,length 0 E ..(.. @。@ ...... m .... 5..g ... Ap。 P ....... `
无SYN/ACK应答的情况下: 14:16:18.719629 IP 223.151.224.61.13579 > localhost.5223: Flags [S], seq 123456, win 4096, length 0 E..([email protected][email protected] 14:16:46.511299 IP 240.151.224.61.13579 > localhost.5223: Flags [S], seq 123456, win 4096, length 0 E..([email protected][email protected]$X..
服务器没有回复我,除非iphdr.saddr被设置为多播类型地址 – qingfeng 2014-10-31 07:11:51