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Please, reopen this question. I really need to understand how to do this - And i saw that a lot of other users have this same problem but no one answered them...

I tried to exemplify with clarity showing even a image of a device that is working like that - Please reopen the question so people can help me?

Thanks!

My network structure has a switch where the gateway is 192.168.1.254, and my computer has the IP address 192.168.17.16

I want to continue using this IP address and use the gateway 192.168.1.254 Why?

To avoid conflicts with another networks - And also, i have a BUNCH of Firewall rules configured for 192.168.17.16.

Is this possible?

I saw a server once that had IP 10.10.1.120 and had a totally different gateway!! It worked just fine but i have no clue on how they did it.

Thanks in advance!

To clarify what i want, here is a example, so it will help you guys understand this question better:

Example

This device achieved what i am trying to do. It has a IP address of 10.99.98.121 and its currently using the same gateway i use on my computer - Which is 192.168.31.254

How?

Raul Chiarella
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1 Answers1

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You can achieve this by defining the default gateway adress and the connection/interface used to reach it. By default your system only knows how to reach the locally defined subnet (I guess it's a /24 network mask, so you can reach adresses 192.168.17.1 to 192.168.17.254 without any changes). Now you must tell it the address of the gateway and which interface is connected to it.

E.g.: You have interface eth0 connected to your LAN with IP 192.168.17.16 and netmask 24 (= 255.255.255.0), then you define the default gateway by saying "default gw is 192.168.1.254 reachable via eth0".

With CentOS7 the network managment is done by NetworkManager. You can use the cli to setup the default gateway:

sudo nmcli connection modify eth0 ipv4.gateway "192.168.1.254"
sudo nmcli connection up eth0

See also https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/networking_guide/sec-configuring_static_routes_using_nmcli

You can also modify configuraton files directly by following this guide: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/networking_guide/sec-configuring_static_routes_in_ifcfg_files

Edit (as I can't post comments):

You can connect to any address that is reachable via a physically connected network. The poster didn't tell us if there are multiple physical networks involved and if there is some dedicated router that does the connection between the networks. Therefore I suggest he can reach the gateway directly and only needs to tell his system which interface to use.

puldi
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