Alias on the loopback is not reachable

pcoustaux — Thu, 05 Jun 2025 06:09:07 GMT

Hi,

I am working in a multi-lan infrastructure (really multi-switch) and my filer is attached to both of theses.

The solution used for such other device is to put a routable ip on the loopback and let the ip stack do it's routing job.

On the netapp, i was able to add an alias/32 on the loopback, but this ip stay unreachable from the outside.

I have attempted with fastpath enabled/disabled

using routed or not.

Any idea ?

Thanks for your help.

/Philippe

Re: Alias on the loopback is not reachable

aborzenkov — Wed, 27 Feb 2013 11:09:25 GMT

You do not explain what you intend to achieve so it is hard to have any ideas.

Please paste “ifconfig -a” and explain which additional IP addresses you want to configure.

pcoustaux — Wed, 27 Feb 2013 11:52:34 GMT

Sorry for the bad description.

<= routed Lan Infrastructure1 192.168.22.x => || e0c..The filer..e0d || <= 193.168.22.x routed Lan Infrastructure2 =>

I have two independant routed infrastructure, as a shared device the filer will be connected to both.

I want that the ressources of the filer can be reach and used with the same ip on the 2 lan infrastructures.

Here in the simulator, i have e0c (192.168.22.8) on one switch, e0d(193.168.22.10) on an other independant switch. (no lacp)

I put an alias on the loopback (192.168.250.1), the network1 kown that the gateway to reach this ip is through e0c ip

the network2 known that to reach this ip is through e0d ip.

And i would expect that a mount/http using this ip works from both side.

The routing is correct, and even the ping don't work 😞

e0a: flags=0xe48867<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500

inet 193.168.70.110 netmask 0xffffff00 broadcast 193.168.70.255

ether 00:50:56:ad:2e:da (auto-1000t-fd-up) flowcontrol full

e0b: flags=0x608866<BROADCAST,RUNNING,MULTICAST> mtu 1500

ether 00:50:56:ad:2e:db (auto-unknown-down) flowcontrol full

e0c: flags=0xe48867<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500

inet 192.168.22.8 netmask 0xffffff00 broadcast 192.168.22.255

ether 00:50:56:ad:2e:dc (auto-1000t-fd-up) flowcontrol full

e0d: flags=0xe48867<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500

inet 193.168.22.10 netmask 0xffffff00 broadcast 193.168.22.255

ether 00:50:56:ad:2e:dd (auto-1000t-fd-up) flowcontrol full

lo: flags=0x1b48049<UP,LOOPBACK,RUNNING,MULTICAST,TCPCKSUM> mtu 9188

inet 127.0.0.1 netmask 0xff000000 broadcast 127.0.0.1

inet 192.168.250.1 netmask 0xffffff00 broadcast 192.168.250.1

losk: flags=0x40a400c9<UP,LOOPBACK,RUNNING> mtu 9188

inet 127.0.20.1 netmask 0xff000000 broadcast 127.0.20.1