linux gre隧道创建

实验环境

两台可以相互通信的虚拟机，两个虚拟机在不通的网段。如下所示

host A:

[[email protected] ~]# ip a

1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

inet 127.0.0.1/8 scope host lo

valid_lft forever preferred_lft forever

2: eth0: mtu 1454 qdisc pfifo_fast state UP group default qlen 1000

link/ether 52:54:00:f6:21:28 brd ff:ff:ff:ff:ff:ff

inet 10.10.10.47/24 brd 10.10.10.255 scope global eth0

valid_lft forever preferred_lft forever

host B:

[[email protected] ~]# ip a

1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

inet 127.0.0.1/8 scope host lo

valid_lft forever preferred_lft forever

2: eth0: mtu 1454 qdisc pfifo_fast state UP group default qlen 1000

link/ether 52:54:00:14:91:76 brd ff:ff:ff:ff:ff:ff

inet 192.168.0.118/24 brd 192.168.0.255 scope global eth0

valid_lft forever preferred_lft forever

两台虚拟机之间可以相互通信

[[email protected] ~]# ping 10.10.10.47

PING 10.10.10.47 (10.10.10.47) 56(84) bytes of data.

64 bytes from 10.10.10.47: icmp_seq=1 ttl=63 time=1.04 ms

64 bytes from 10.10.10.47: icmp_seq=2 ttl=63 time=0.440 ms

64 bytes from 10.10.10.47: icmp_seq=3 ttl=63 time=0.368 ms

64 bytes from 10.10.10.47: icmp_seq=4 ttl=63 time=0.561 ms

^C

--- 10.10.10.47 ping statistics ---

4 packets transmitted, 4 received, 0% packet loss, time 3001ms

rtt min/avg/max/mdev = 0.368/0.602/1.040/0.262 ms

实验目的

在host A和host B之间建里gre隧道，另外在机器A 上面配置 2.2.2.2， 在机器B上面配置1.1.1.1 ，然后在A上面能够ping -I 2.2.2.2 1.1.1.1 能够通。

实验步骤

1、在host A(10.10.10.47)上面操作

ip tunnel add gre-test mode gre remote 192.168.0.118 local 10.10.10.47 ttl 255

ip link set gre-test up

ip route add 1.1.1.1/32 dev gre-test

ip addr add 2.2.2.2 dev gre-test

ip link set gre-test down

操作过程入下图

[[email protected] ~]# ip tunnel add gre-test mode gre remote 192.168.0.118 local 10.10.10.47 ttl 255

[[email protected] ~]# ip link set gre-test up

[[email protected] ~]# ip route add 1.1.1.1/32 dev gre-test

[[email protected] ~]# ip addr add 2.2.2.2 dev gre-test

[[email protected] ~]# ip a

1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

inet 127.0.0.1/8 scope host lo

valid_lft forever preferred_lft forever

2: eth0: mtu 1454 qdisc pfifo_fast state UP group default qlen 1000

link/ether 52:54:00:f6:21:28 brd ff:ff:ff:ff:ff:ff

inet 10.10.10.47/24 brd 10.10.10.255 scope global eth0

valid_lft forever preferred_lft forever

3: [email protected]: mtu 1476 qdisc noop state DOWN group default qlen 1000

link/gre 0.0.0.0 brd 0.0.0.0

4: [email protected]: mtu 1462 qdisc noop state DOWN group default qlen 1000

link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff

5: [email protected]: mtu 1430 qdisc noqueue state UNKNOWN group default qlen 1000

link/gre 10.10.10.47 peer 192.168.0.118

inet 2.2.2.2/32 scope global gre-test

valid_lft forever preferred_lft forever

[[email protected] ~]# ip r

default via 10.10.10.1 dev eth0

1.1.1.1 dev gre-test scope link

10.10.10.0/24 dev eth0 proto kernel scope link src 10.10.10.47

2、在host B(192.168.0.118)上面操作

ip tunnel add gre-test mode gre remote 10.10.10.47 local 192.168.0.118 ttl 255

ip link set gre-test up

ip route add 2.2.2.2/32 dev gre-test

ip addr add 1.1.1.1 dev gre-test

ip link set gre-test down

[[email protected] ~]# ip tunnel add gre-test mode gre remote 10.10.10.47 local 192.168.0.118 ttl 255

[[email protected] ~]# ip link set gre-test up

[[email protected] ~]# ip route add 2.2.2.2/32 dev gre-test

[[email protected] ~]# ip addr add 1.1.1.1 dev gre-test

[[email protected] ~]# ip a

1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

inet 127.0.0.1/8 scope host lo

valid_lft forever preferred_lft forever

2: eth0: mtu 1454 qdisc pfifo_fast state UP group default qlen 1000

link/ether 52:54:00:14:91:76 brd ff:ff:ff:ff:ff:ff

inet 192.168.0.118/24 brd 192.168.0.255 scope global eth0

valid_lft forever preferred_lft forever

3: [email protected]: mtu 1476 qdisc noop state DOWN group default qlen 1000

link/gre 0.0.0.0 brd 0.0.0.0

4: [email protected]: mtu 1462 qdisc noop state DOWN group default qlen 1000

link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff

6: [email protected]: mtu 1430 qdisc noqueue state UNKNOWN group default qlen 1000

link/gre 192.168.0.118 peer 10.10.10.47

inet 1.1.1.1/32 scope global gre-test

valid_lft forever preferred_lft forever

[[email protected] ~]# ip r

default via 192.168.0.1 dev eth0

2.2.2.2 dev gre-test scope link

192.168.0.0/24 dev eth0 proto kernel scope link src 192.168.0.118

实验结果

[[email protected] ~]# ping -I 2.2.2.2 1.1.1.1 -c 4

PING 1.1.1.1 (1.1.1.1) from 2.2.2.2 : 56(84) bytes of data.

64 bytes from 1.1.1.1: icmp_seq=1 ttl=64 time=0.635 ms

64 bytes from 1.1.1.1: icmp_seq=2 ttl=64 time=0.702 ms

64 bytes from 1.1.1.1: icmp_seq=3 ttl=64 time=0.588 ms

64 bytes from 1.1.1.1: icmp_seq=4 ttl=64 time=0.565 ms

--- 1.1.1.1 ping statistics ---

4 packets transmitted, 4 received, 0% packet loss, time 3000ms

rtt min/avg/max/mdev = 0.565/0.622/0.702/0.058 ms

还原实验环境

在host A(10.10.10.47)执行

ip link set gre-test down

ip tunnel del gre-test

[[email protected] ~]# ip link set gre-test down

[[email protected] ~]# ip tunnel del gre-test

[[email protected] ~]# ip a

1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

inet 127.0.0.1/8 scope host lo

valid_lft forever preferred_lft forever

2: eth0: mtu 1454 qdisc pfifo_fast state UP group default qlen 1000

link/ether 52:54:00:f6:21:28 brd ff:ff:ff:ff:ff:ff

inet 10.10.10.47/24 brd 10.10.10.255 scope global eth0

valid_lft forever preferred_lft forever

3: [email protected]: mtu 1476 qdisc noop state DOWN group default qlen 1000

link/gre 0.0.0.0 brd 0.0.0.0

4: [email protected]: mtu 1462 qdisc noop state DOWN group default qlen 1000

link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff

在host B(192.168.0.118)执行

ip link set gre-test down

ip tunnel del gre-test

[[email protected] ~]# ip link set gre-test down

[[email protected] ~]# ip tunnel del gre-test

[[email protected] ~]# ip a

1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

inet 127.0.0.1/8 scope host lo

valid_lft forever preferred_lft forever

2: eth0: mtu 1454 qdisc pfifo_fast state UP group default qlen 1000

link/ether 52:54:00:14:91:76 brd ff:ff:ff:ff:ff:ff

inet 192.168.0.118/24 brd 192.168.0.255 scope global eth0

valid_lft forever preferred_lft forever

3: [email protected]: mtu 1476 qdisc noop state DOWN group default qlen 1000

link/gre 0.0.0.0 brd 0.0.0.0

4: [email protected]: mtu 1462 qdisc noop state DOWN group default qlen 1000

link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff

最后还有一个gre0，不能用

ip link set gre0 down

ip tunnel del gre0

上面两个命令删除，否则会报错

[[email protected] ~]# ip link set gre0 down

[[email protected] ~]# ip tunnel del gre0

delete tunnel “gre0” failed: Operation not permitted

需要按照下面的命令删除：

[[email protected] ~]# lsmod|grep gre

ip_gre 22931 0

gre 13144 1 ip_gre

ip_tunnel 25163 1 ip_gre

[[email protected] ~]# rmmod ip_gre

[[email protected] ~]# ip a

1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

inet 127.0.0.1/8 scope host lo

valid_lft forever preferred_lft forever

2: eth0: mtu 1454 qdisc pfifo_fast state UP group default qlen 1000

link/ether 52:54:00:14:91:76 brd ff:ff:ff:ff:ff:ff

inet 192.168.0.118/24 brd 192.168.0.255 scope global eth0

valid_lft forever preferred_lft forever

[[email protected] ~]#

整个实验过程比较简单，自己操作一遍才能把这些基本的命令熟悉起来。

原文：https://www.cnblogs.com/0pandas0/p/12005218.html