Network Related Clarification

General support questions
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sysarun86
Posts: 10
Joined: 2022/04/06 08:33:13

Network Related Clarification

Post by sysarun86 » 2024/05/06 05:50:55

It is possible to set same subnet series IP Address for both interface?

in centos 7 having two network interface card both card having different static IP address with same subnet mask,
i checked Receive and transmit packets in both interface,
it seems like one interface having around 20MBPS and another interface only 150KBPS,
it seems like all network traffic goes on single interface

IP Route Table Mentioned Below,

ip route show
default via 192.168.0.28 dev em3 proto static metric 102
default via 192.168.0.28 dev em4 proto static metric 103
192.168.0.0/22 dev em3 proto kernel scope link src 192.168.0.60 metric 102
192.168.0.0/22 dev em4 proto kernel scope link src 192.168.0.48 metric 103
192.168.122.0/24 dev virbr0 proto kernel scope link src 192.168.122.1

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jlehtone
Posts: 4551
Joined: 2007/12/11 08:17:33
Location: Finland

Re: Network Related Clarification

Post by jlehtone » 2024/05/06 07:06:56

sysarun86 wrote:
2024/05/06 05:50:55
it seems like all network traffic goes on single interface
The first/most specific/highest priority rule for "to 192.168.0.0/22" is:
192.168.0.0/22 dev em3 proto kernel scope link src 192.168.0.60 metric 102
so that is used for practically all traffic.
sysarun86 wrote:
2024/05/06 05:50:55
It is possible to set same subnet series IP Address for both interface?
It is "technically possible", but one should not do that. The issue is not about the interfaces,
but about having more than one address on same subnet.

If the purpose of linking more than one interface to same subnet is redundancy and/or bandwidth,
then one should look at bonding or teamd. (The latter appeared in el7, but is already
deprecated in el9, so is not worth learning.) Their idea is that multiple physical links form one
logical connection (that has one IP address). They may require something from the device(s) that
the wires go to.


Note though that CentOS 7 will be dead, End-of-Life, by end of June 2024. Next month.
It is high time to find a new distro for your system.

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