TCP/IP 详解 卷1 ch3 IP

1. IP RFC 791, unreliable and connectionless

2. big endian: 网络字节序

3. TTL : time to live, 设置了数据报可以经过的最多路由器数

4. 子网寻址： IP = 网络号 + 子网号 + 主机号， 缩减路由表规模

子网掩码 = 网络号 + 子网号 全1

5. 特殊的IP

网络号为127，主机号为任意值，均可表示loopback地址

6. ifconfig 命令

/home/a/j/nomad2:ifconfig -a
lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu 8232 index 1
inet 127.0.0.1 netmask ff000000
e1000g0: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 2
inet 192.168.1.10 netmask ffffff00 broadcast 192.168.1.255
lo0: flags=2002000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv6,VIRTUAL> mtu 8252 index 1
inet6 ::1/128
e1000g0: flags=2000841<UP,RUNNING,MULTICAST,IPv6> mtu 1500 index 2
inet6 fe80::214:4fff:fe45:f196/10

7. netstat 命令

/home/a/j/nomad2:netstat -in
Name  Mtu  Net/Dest      Address        Ipkts  Ierrs Opkts  Oerrs Collis Queue
lo0   8232 127.0.0.0     127.0.0.1      462088 0     462088 0     0      0
e1000g0 1500 192.168.1.0   192.168.1.10   154328357 0     139467292 0     0      0
Name  Mtu  Net/Dest                    Address                     Ipkts  Ierrs Opkts  Oerrs Collis
lo0   8252 ::1                         ::1                         462088 0     462088 0     0
e1000g0 1500 fe80::214:4fff:fe45:f196/10 fe80::214:4fff:fe45:f196    154328357 0     139467293 0     0