很久很久之前搞Linux端口转发时，借了一台三层交换机，我拿到手还没拆包装箱。不知道是不是因为工作上的这个原因而买的。不过后来实现的端口转发和三层交换机完全不搭边，就不了了之了。现在领导安排我查查广播风暴的事情，在同一网段里测试过了，就想在不同网段里试试，于是又借了这一台。这次是认真学习了一些配置命令，不过网上大把这类的资料，这里根据资料结合自己的实践，记录一下。
这次要做的是将三层交换机划分3个vlan，分别是192.168.1、2、3段。
<H3C>sys
vlan 10：创建vlan并进入，加入1~8
[H3C]vlan 10
[H3C-vlan10]port e1/0/1 to e1/0/8
[H3C-vlan10]q
创建vlan 20，加入9~16
[H3C]vlan 20
[H3C-vlan20]port e1/0/9 to e1/0/16
[H3C-vlan20]q
创建vlan 30，加入17~24
[H3C]vlan 30
[H3C-vlan30]port e1/0/17 to e1/0/24
[H3C-vlan30]q
显示有哪些vlan
[H3C]dis vlan
Total 4 VLAN exist(s).
The following VLANs exist:
1(default), 10, 20, 30,
每个VLAN分别添加IP、子网掩码：
[H3C]int vlan 10
[H3C-Vlan-interface10]ip addr 192.168.1.254 255.255.255.0
[H3C-Vlan-interface10]quit
[H3C]int vlan 20
[H3C-Vlan-interface20]ip addr 192.168.2.254 255.255.255.0
[H3C-Vlan-interface20]quit
[H3C]int vlan 30
[H3C-Vlan-interface30]ip addr 192.168.3.254 255.255.255.0
[H3C-Vlan-interface30]quit
[H3C]
这里添加的vlan的IP，结合后面的验证，是接入设备的网关地址。
在接入vlan的设备上设置好IP和网关，信息如下：
root@localhost:~# route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default 192.168.1.254 0.0.0.0 UG 0 0 0 eth0
192.168.1.0 * 255.255.255.0 U 0 0 0 eth0
root@localhost:~# ifconfig eth0
eth0 Link encap:Ethernet HWaddr 88:55:33:44:11:88
inet addr:192.168.1.100 Bcast:192.168.1.255 Mask:255.255.255.0
inet6 addr: ff90::3411:89ff:fe0d:f987/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:939 errors:0 dropped:0 overruns:0 frame:0
TX packets:277 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:86165 (86.1 KB) TX bytes:47595 (47.5 KB)
Memory:90400000-9041ffff
在该设备上ping vlan20中的设备，是ping得通的，抓包信息如下：
root@localhost:~# tcpdump net 192.168.2.101
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
11:28:55.413927 IP 192.168.1.100.ssh > 192.168.2.101.59431: Flags [P.], seq 699346371:699346567, ack 3447371143, win 255, length 196
11:28:55.413972 IP 192.168.1.100.ssh > 192.168.2.101.59431: Flags [P.], seq 196:248, ack 1, win 255, length 52
11:29:04.427973 IP 192.168.1.100.ssh > 192.168.2.101.59431: Flags [P.], seq 3648:3908, ack 1, win 255, length 260
11:29:06.430510 IP 192.168.1.100.ssh > 192.168.2.101.59431: Flags [P.], seq 4168:4428, ack 1, win 255, length 260
11:29:06.501987 IP 192.168.2.101 > 192.168.1.100: ICMP echo request, id 1, seq 108, length 40
11:29:06.502120 IP 192.168.1.100 > 192.168.2.101: ICMP echo reply, id 1, seq 108, length 40
11:29:06.630739 IP 192.168.2.101.59431 > 192.168.1.100.ssh: Flags [.], ack 4428, win 251, length 0
11:29:07.431587 IP 192.168.1.100.ssh > 192.168.2.101.59431: Flags [P.], seq 4428:4592, ack 1, win 255, length 164
11:29:07.431637 IP 192.168.1.100.ssh > 192.168.2.101.59431: Flags [P.], seq 4592:4740, ack 1, win 255, length 148
11:29:07.432016 IP 192.168.1.100.ssh > 192.168.2.101.59431: Flags [P.], seq 4740:5020, ack 1, win 255, length 280
11:29:07.504812 IP 192.168.2.101 > 192.168.1.100: ICMP echo request, id 1, seq 109, length 40
11:29:07.504935 IP 192.168.1.100 > 192.168.2.101: ICMP echo reply, id 1, seq 109, length 40
在该交换机上搞个环路，能检测到有冲突：
%Jan 1 07:12:31:498 2010 H3C ARP/5/ARP_DUPLICATE_IPADDR_DETECT: Detected an IP address conflict. The device with MAC address f0fe-f1fa-5cfe1 connected to Ethernet1/0/5 in VLAN 10 and the device with MAC address ffde-f11c-3414 connected to Ethernet1/0/3 in VLAN 10 are using the same IP address 192.168.1.101.
%Jan 1 07:12:31:888 2010 H3C ARP/5/ARP_DUPLICATE_IPADDR_DETECT: Detected an IP address conflict. The device with MAC address f0de-f1eb-5e31 connected to Ethernet1/0/3 in VLAN 10 and the device with MAC address ffde-f1eb-1378 connected to Ethernet1/0/5 in VLAN 10 are using the same IP address 192.168.1.101.
%Jan 1 07:12:32:269 2010 H3C ARP/5/ARP_DUPLICATE_IPADDR_DETECT: Detected an IP address conflict. The device with MAC address f0ee-f1eb-5e31 connected to Ethernet1/0/5 in VLAN 10 and the de
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作者：李迟
来源：CSDN
原文：https://blog.csdn.net/subfate/article/details/44901337
版权声明：本文为博主原创文章，转载请附上博文链接！