Static IP address without a gateway
You do not need a gateway
entry for any NIC that you don't want to use to reach a network not in its collision domain (192.168/16 in this case). You can just omit that line if you don't want a gateway for that NIC.
I'm not sure what will happen if you try to use loopback as a gateway, but I wouldn't expect it to be happy times.
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111---
Updated on September 18, 2022Comments
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111--- over 1 year
Simple setup here. I have a machine with multiple network interfaces, two for example -
eth0
andeth1
.eth0
has a static address and has a default gateway assigned.eth1
has a static address and will not have a gateway on that interface's network address range.The Question
Do I need an entry in network configuration file (
/etc/network/interfaces
) for thegateway
option on the interface that does not have a gateway on its network,eth1
in the above example?Additional Questions
If I do something like:
gateway 127.0.0.1
Will this have adverse effects? Will this interface now have a way to reach a gateway or will using the loopback interface as a gateway have no effect (i.e. same as leaving the
gateway
option off entirely)?Example config for discussion
/etc/network/interfaces
# The loopback network interface auto lo iface lo inet loopback # Interface 1 allow-hotplug eth0 iface eth0 inet static address 10.1.10.200 netmask 255.255.255.0 gateway 10.1.10.1 # Interface 2 allow-hotplug eth1 iface eth1 inet static address 192.168.100.1 netmask 255.255.0.0 gateway 127.0.0.1 # This is the line in question
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zwets over 8 yearsI haven't tested but I would guess that trying to set 127.0.0.1 as a gateway for 192.168.100.1 will not work because they are in disjoint networks: 127/8 vs 192.168/16.