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Old 04-06-2017, 05:03 AM   #1
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Registered: Jan 2015
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Gateway does not route host alias interfaces


How can I get alias interfaces packages routed by a Linux gateway?

Seems I do not understand how work alias interfaces.

I have a Linux gateway that does not route packets from alias interfaces from hosts in any subset, but it does with real interface packets.

First I guessed the problem came from arp table, as 2 ip have the same mac address. As it seems to be impossible to add "independent" mac address to alias interfaces, I tried to delete arp entry associated with the physical ip, but nothing happens. The gateway still does not reach the virtual interface. I get "***" on traceroute command in the gateway site, while all other hosts, "stuck on the gateway".

What I tried :
- added clone interfaces with files, and ip command on needed hosts;
- added host route in the gateway (ip of alias interfaces);
- added firewall rules;
- added/delete arp entry;

Old 04-06-2017, 03:43 PM   #2
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Can you give the output of "ip addr" and "ip route"? feel free to x out the ips themselves if you don't want to display them. But hard to really give you any information without at least a bit of basic info.
Old 09-21-2017, 11:47 AM   #3
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Registered: Mar 2011
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I am going to reopen this issue, as it seems to be the same problem I am experiencing. I searched the Red Hat KB and did not find a solution there. Anyway, here is the issue.

I want the alias device (e.g., eth0:0) to route traffic for a different network through eth1. The traffic for eth0 will route properly though the configured route through eth1, but the traffic received on eth0:0 will not. For example, eth0 has IP and traffic to a host at routes through eth1 with a static route to But when that traffic is received to eth0:0, which has the IP, the route is ignored and I see in the packet capture that the source is that of eth0:0 ( trying to reach Is it possible to get the alias configured on eth0 to route through eth1 to the network?


alias, arp, gateway, mac, routing

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