metric

metric

配置网卡的默认metric

给网卡配置默认的metric值,当添加路由的时候如果没有手动指定 metric 值,则使用默认值,默认值为 -1 ,表示自动配置路由的metric值。metric 数值越大,路由的优先级越低。

没有 NetworkManager 的情况下设置

修改位于/etc/sysconfig/network-scripts/目录下的ifcfg-<interface>文件,<interface>是接口的名称,添加以下内容

METRIC=XXXX

重新启动network服务生效

service network restart

使用 NetworkManager 配置metric

使用nmclinmtui ,或者GUI修改路由的Metric

例如,添加一条名为的连接external 的 metric

nmcli connection modify external ipv4.route-metric 600

重新加载连接生效

nmcli connection up external

注意:ipv4.route-metric 参数可以更改所有该连接对应网卡的所有路由的 metric 值,但是。。。对应手动指定了metric 值的路由,是不会修改的。也就是配置网卡的默认metric,-1表示自动配置metric

[root@oracle-linux7-9-5 ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         10.0.0.2        0.0.0.0         UG    100    0        0 ens33
10.0.0.0        0.0.0.0         255.255.255.0   U     100    0        0 ens33
172.16.0.0      0.0.0.0         255.255.255.0   U     105    0        0 ens35
172.16.1.0      0.0.0.0         255.255.255.0   U     600    0        0 ens36
192.168.1.0     172.16.0.1      255.255.255.0   UG    105    0        0 ens35
192.168.1.0     172.16.1.1      255.255.255.0   UG    600    0        0 ens36
[root@oracle-linux7-9-5 ~]# nmcli connection show vpn2 | grep -E 'routes|metric|ens36'
connection.interface-name:              ens36
ipv4.routes:                            { ip = 192.168.1.0/24, nh = 172.16.1.1 }
ipv4.route-metric:                      600
ipv4.ignore-auto-routes:                no
ipv6.routes:                            --
ipv6.route-metric:                      -1
ipv6.ignore-auto-routes:                no
GENERAL.DEVICES:                        ens36

# 可以看到网络连接vpn2,对应的路由条目没有指定metric值,所以该网卡对应的所有路由条目的metric值都是ipv4.route-metric的值

范例:手动修改路由的metric值

[root@oracle-linux7-9-5 ~]# nmcli connection modify vpn2 ipv4.routes '192.168.1.0/24 172.16.1.1 300'
[root@oracle-linux7-9-5 ~]# nmcli connection up vpn2
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/16)
[root@oracle-linux7-9-5 ~]# route -n | grep ens36
172.16.1.0      0.0.0.0         255.255.255.0   U     600    0        0 ens36
192.168.1.0     172.16.1.1      255.255.255.0   UG    300    0        0 ens36

修改路由的优先级

没有 NetworkManager 的情况下设置

创建或修改位于/etc/sysconfig/network-scripts/目录下route-<interface>文件,<interface>是网卡接口的名称

文件的格式如下

<network/prefix> via <gateway> <metric "value">
<network/prefix>	指定目标IP或者网段
<gateway>			指定下一跳的地址
<metric "value">	指定路由的优先级,metric值越高,路由的优先级越低

范例:

# cat /etc/sysconfig/network-scripts/route-<interface>
10.0.0.0/24 via 192.51.100.10 metric 200
10.0.1.0/24 via 192.51.10.20 metric 50

让路由生效

ifup <interface>

使用 NetworkManager 配置metric

  • 修改现有连接的metric

    nmcli connection modify ens192 ipv4.routes "10.0.0.0/24 192.51.100.10 400"
    
  • 为一条连接添加路由并配置metric

    nmcli connection modify external +ipv4.routes "10.0.0.0/24 192.0.2.30 350"
    

让配置生效

nmcli connection up ens192

大小路由优先级

在路由表中既有大路由,又包含小的路由,例如下面这种

10.0.0.0/16 via 192.51.100.10 metric 200	# 大路由
10.0.0.0/24 via 192.51.10.20 metric 50		# 小路由

实验环境

小路由VPN1,网卡ens35,对应网关172.16.0.1

大路由VPN2,网卡ens36,对应网关172.16.1.1

# 配置小路由
[root@oracle-linux7-9-5 ~]# nmcli connection modify vpn1 ipv4.routes '192.168.1.0/24 172.16.0.1 200'
[root@oracle-linux7-9-5 ~]# nmcli connection show vpn1 | egrep 'metric|routes|ens35'
connection.interface-name:              ens35
ipv4.routes:                            { ip = 192.168.1.0/24, nh = 172.16.0.1, mt = 200 }
ipv4.route-metric:                      -1
ipv4.ignore-auto-routes:                no
ipv6.routes:                            --
ipv6.route-metric:                      -1
ipv6.ignore-auto-routes:                no
GENERAL.DEVICES:                        ens35

# 配置大路由
[root@oracle-linux7-9-5 ~]# nmcli connection modify vpn2 ipv4.routes '192.168.0.0/16 172.16.1.1 200'
[root@oracle-linux7-9-5 ~]# nmcli connection up vpn2
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/30)
[root@oracle-linux7-9-5 ~]# nmcli connection show vpn2 | egrep 'metric|routes|ens36'
connection.interface-name:              ens36
ipv4.routes:                            { ip = 192.168.0.0/16, nh = 172.16.1.1, mt = 200 }
ipv4.route-metric:                      -1
ipv4.ignore-auto-routes:                no
ipv6.routes:                            --
ipv6.route-metric:                      -1
ipv6.ignore-auto-routes:                no
GENERAL.DEVICES:                        ens36

# 最终路由,大路由的网关是172.16.1.1,小路由是172.16.0.1
[root@oracle-linux7-9-5 ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         10.0.0.2        0.0.0.0         UG    100    0        0 ens33
10.0.0.0        0.0.0.0         255.255.255.0   U     100    0        0 ens33
172.16.0.0      0.0.0.0         255.255.255.0   U     113    0        0 ens35
172.16.1.0      0.0.0.0         255.255.255.0   U     114    0        0 ens36
192.168.0.0     172.16.1.1      255.255.0.0     UG    200    0        0 ens36
192.168.1.0     172.16.0.1      255.255.255.0   UG    200    0        0 ens35


# 发现是小的路由优先生效
[root@oracle-linux7-9-5 ~]# traceroute -n 192.168.1.9
traceroute to 192.168.1.9 (192.168.1.9), 30 hops max, 60 byte packets
 1  172.16.0.1  0.621 ms  0.569 ms  0.564 ms
 2  192.168.1.9  1.071 ms  1.112 ms  1.108 ms

担心是添加路由的顺序导致,小路由在前,路由表优先匹配,删除大小路由重新测试

# 删除大小路由
nmcli connection modify vpn1 ipv4.routes ''
nmcli connection up vpn1
nmcli connection modify vpn2 ipv4.routes ''
nmcli connection up vpn2
# 这次先添加大路由,后添加小路由
nmcli connection modify vpn2 ipv4.routes '192.168.0.0/16 172.16.1.1 200'
nmcli connection up vpn2
nmcli connection modify vpn1 ipv4.routes '192.168.1.0/24 172.16.0.1 200'
nmcli connection up vpn1
# 最终路由表依然是大路由出现在了前面,目前metric相同,开始测试
[root@oracle-linux7-9-5 ~]# traceroute -n 192.168.1.9
traceroute to 192.168.1.9 (192.168.1.9), 30 hops max, 60 byte packets
 1  172.16.0.1  0.810 ms  0.764 ms  0.760 ms
 2  192.168.1.9  1.223 ms  1.218 ms  1.214 ms
 `最终还是走小路由`

降低小路由metric值,也就是提高他的优先级,看看效果

[root@oracle-linux7-9-5 ~]# nmcli connection show vpn1 | egrep 'metric|routes|ens36'
ipv4.routes:                            { ip = 192.168.0.0/16, nh = 172.16.1.1, mt = 200 }
ipv4.route-metric:                      -1
ipv4.ignore-auto-routes:                no
ipv6.routes:                            --
ipv6.route-metric:                      -1
ipv6.ignore-auto-routes:                no

# 修改metric值
[root@oracle-linux7-9-5 ~]# nmcli connection modify vpn1 ipv4.routes '192.168.0.0/24 172.16.0.1 1'
[root@oracle-linux7-9-5 ~]# nmcli connection up vpn1
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/27)
[root@oracle-linux7-9-5 ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         10.0.0.2        0.0.0.0         UG    100    0        0 ens33
10.0.0.0        0.0.0.0         255.255.255.0   U     100    0        0 ens33
172.16.0.0      0.0.0.0         255.255.255.0   U     111    0        0 ens35
172.16.1.0      0.0.0.0         255.255.255.0   U     110    0        0 ens36
192.168.0.0     172.16.0.1      255.255.255.0   UG    1      0        0 ens35
192.168.0.0     172.16.1.1      255.255.0.0     UG    200    0        0 ens36
# 发现还是大的路由生效
[root@oracle-linux7-9-5 ~]# traceroute -n 192.168.1.9
traceroute to 192.168.1.9 (192.168.1.9), 30 hops max, 60 byte packets
 1  172.16.1.1  0.613 ms  0.563 ms  0.534 ms
 2  192.168.1.9  0.999 ms  0.955 ms  0.922 ms

小路由优先级更高

删除大路由测试小路由是否生效

[root@oracle-linux7-9-5 ~]# nmcli connection modify vpn2 ipv4.routes ''
[root@oracle-linux7-9-5 ~]# nmcli connection up vpn2
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/28)
[root@oracle-linux7-9-5 ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         10.0.0.2        0.0.0.0         UG    100    0        0 ens33
10.0.0.0        0.0.0.0         255.255.255.0   U     100    0        0 ens33
172.16.0.0      0.0.0.0         255.255.255.0   U     119    0        0 ens35
172.16.1.0      0.0.0.0         255.255.255.0   U     120    0        0 ens36
192.168.1.0     172.16.0.1      255.255.255.0   UG    200    0        0 ens35
[root@oracle-linux7-9-5 ~]# traceroute -n 192.168.1.9
traceroute to 192.168.1.9 (192.168.1.9), 30 hops max, 60 byte packets
 1  172.16.0.1  0.671 ms  0.620 ms  0.586 ms
 2  192.168.1.9  0.792 ms  0.759 ms  0.722 ms

删除小路由测试大路由是否生效

[root@oracle-linux7-9-5 ~]# nmcli connection modify vpn1 ipv4.routes ''
[root@oracle-linux7-9-5 ~]# nmcli connection up vpn1
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/41)
[root@oracle-linux7-9-5 ~]# nmcli connection modify vpn2 ipv4.routes ''
[root@oracle-linux7-9-5 ~]# nmcli connection up vpn2
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/42)
[root@oracle-linux7-9-5 ~]# nmcli connection modify vpn2 ipv4.routes '192.168.0.0/16 172.16.1.1 200'
[root@oracle-linux7-9-5 ~]# nmcli connection up vpn2
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/43)
[root@oracle-linux7-9-5 ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         10.0.0.2        0.0.0.0         UG    100    0        0 ens33
10.0.0.0        0.0.0.0         255.255.255.0   U     100    0        0 ens33
172.16.0.0      0.0.0.0         255.255.255.0   U     121    0        0 ens35
172.16.1.0      0.0.0.0         255.255.255.0   U     122    0        0 ens36
192.168.0.0     172.16.1.1      255.255.0.0     UG    200    0        0 ens36
[root@oracle-linux7-9-5 ~]# traceroute -n 192.168.1.9
traceroute to 192.168.1.9 (192.168.1.9), 30 hops max, 60 byte packets
 1  172.16.1.1  0.611 ms  0.559 ms  0.605 ms
 2  192.168.1.9  1.247 ms  1.242 ms  1.239 ms

提高大路由的metric,看看效果

[root@oracle-linux7-9-5 ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         10.0.0.2        0.0.0.0         UG    100    0        0 ens33
10.0.0.0        0.0.0.0         255.255.255.0   U     100    0        0 ens33
172.16.0.0      0.0.0.0         255.255.255.0   U     125    0        0 ens35
172.16.1.0      0.0.0.0         255.255.255.0   U     124    0        0 ens36
192.168.0.0     172.16.1.1      255.255.0.0     UG    200    0        0 ens36
192.168.1.0     172.16.0.1      255.255.255.0   UG    200    0        0 ens35

# 提高大路由优先级
nmcli connection modify vpn2 ipv4.routes '192.168.0.0/16 172.16.1.1 1'
nmcli connection up vpn2
[root@oracle-linux7-9-5 ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         10.0.0.2        0.0.0.0         UG    100    0        0 ens33
10.0.0.0        0.0.0.0         255.255.255.0   U     100    0        0 ens33
172.16.0.0      0.0.0.0         255.255.255.0   U     125    0        0 ens35
172.16.1.0      0.0.0.0         255.255.255.0   U     126    0        0 ens36
192.168.0.0     172.16.1.1      255.255.0.0     UG    1      0        0 ens36
192.168.1.0     172.16.0.1      255.255.255.0   UG    200    0        0 ens35
# 测试还是小路由生效
[root@oracle-linux7-9-5 ~]# traceroute -n 192.168.1.9
traceroute to 192.168.1.9 (192.168.1.9), 30 hops max, 60 byte packets
 1  172.16.0.1  0.808 ms  0.749 ms  0.718 ms
 2  192.168.1.9  1.552 ms  1.547 ms  1.543 ms
posted @ 2023-03-09 08:36  18cm的烦恼  阅读(1159)  评论(0编辑  收藏  举报