如果没有从DHCP获取静态IP（脚本） [英] Set static ip if not obtained from DHCP (script)
问题描述
我在linux上使用嵌入式设备。我想先使用DHCP客户端，但如果DHCP服务器没有应答，我想设置静态默认IP。我想这应该不复杂，但我没有找到严格的答案。
I work on embedded device with linux on it. I want to use DHCP client first, but if there will be no answer from DHCP Server I want to set static-default IP. I suppose it shouldn't be complicated, but I haven't found strict answer.
我正在考虑2个解决方案（不幸的是我可以在几天内测试它们） ：
I'm thinking about 2 solutions (Unfortunately I can test them in few days):
-
我用ifconfig设置静态IP，然后调用udhcpc。如果udhcpc无法获得新IP，旧的IP将保留。
I set static IP with ifconfig, then I call udhcpc. If udhcpc will not obtain new IP, old one will stay.
我也可以先调用udhcpc，稍等片刻，检查是否获得了IP。但这对我来说并不好。我不想在启动时添加任何等待例程。
I can also first call udhcpc, wait a while and check if IP is obtained. But this is not nice for me. I wouldn't like to add any wait routines into startup.
BR
Bartek
BR Bartek
我使用udhcpc - 类似于：
I use udhcpc - something like:
udhcpc -n -f -i eth0
if ifconfig | grep -A1 eth0 | grep inet
then
推荐答案
dhclient应支持回退通过租赁声明
查看 dhclient.conf 手册页。
dhclient should support fallback via lease declaration
have a look at the dhclient.conf man page.
添加类似这样的内容到你的 dhclient.conf
Add something like this to your dhclient.conf
timeout 10;
lease {
interface "eth0";
fixed-address 10.0.0.10;
option subnet-mask 255.255.255.0;
renew 2 2022/1/1 00:00:01;
rebind 2 2022/1/1 00:00:01;
expire 2 2022/1/1 0:00:01;
}
或者您可以为接口分配第二个IP，例如 / etc / network / interfaces
or you can assign a second IP to the interface like /etc/network/interfaces
auto lo
iface lo inet loopback
iface eth0 inet dhcp
auto eth0:1
iface eth0:1 inet static
address 10.10.10.2
netmask 255.255.255.0
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