node2发到node1:
02:01:24.190770 IP node2.31684 > node1.webcache: Flags [S], seq 3726408144, win 2560, options [mss 256,sackOK,TS val 117298465 ecr 0,nop,wscale 7], length 0
02:01:24.190806 IP node1.webcache > node2.31684: Flags [S.], seq 1813476634, ack 3726408145, win 1708, options [mss 256,sackOK,TS val 117724869 ecr 117298465,nop,wscale 6], length 0
02:01:24.191144 IP node2.31684 > node1.webcache: Flags [.], ack 1, win 20, options [nop,nop,TS val 117298466 ecr 117724869], length 0
02:01:24.191482 IP node2.31684 > node1.webcache: Flags [.], seq 1:245, ack 1, win 20, options [nop,nop,TS val 117298466 ecr 117724869], length 244
02:01:24.191492 IP node1.webcache > node2.31684: Flags [.], ack 245, win 23, options [nop,nop,TS val 117724870 ecr 117298466], length 0
02:01:24.191585 IP node2.31684 > node1.webcache: Flags [P.], seq 245:258, ack 1, win 20, options [nop,nop,TS val 117298466 ecr 117724869], length 13
02:01:24.191637 IP node1.webcache > node2.31684: Flags [P.], seq 1:70, ack 258, win 23, options [nop,nop,TS val 117724870 ecr 117298466], length 69
02:01:24.192215 IP node2.31684 > node1.webcache: Flags [F.], seq 258, ack 1, win 20, options [nop,nop,TS val 117298466 ecr 117724870], length 0
02:01:24.192551 IP node1.webcache > node2.31684: Flags [FP.], seq 70:303, ack 259, win 23, options [nop,nop,TS val 117724871 ecr 117298466], length 233
02:01:24.193084 IP node2.31684 > node1.webcache: Flags [R], seq 3726408402, win 0, length 0
02:01:24.193885 IP node2.31684 > node1.webcache: Flags [R], seq 3726408403, win 0, length 0
^C
11 packets captured
11 packets received by filter
0 packets dropped by kernel
node1:/root#
为什么一个包大小不是256呢？