[j-nsp] proxy-arp on EVPN irb

[Roger Wiklund]

Hi

It seems that proxy arp is disabled by default:
proxy-arp | Junos OS | Juniper Networks
<https://www.juniper.net/documentation/us/en/software/junos/multicast-l2/topics/ref/statement/proxy-arp-edit-interfaces.html>

Regarding proxy-arp for EVPN (arp suppression) it only works for the same
subnet, not between subnets.

So that seems to match what you're seeing that you must enable proxy-arp on
the IRB in order to reach the other subnets.

Regards
Roger


On Wed, Dec 6, 2023 at 5:04 PM Aaron1 via juniper-nsp <
juniper-nsp at puck.nether.net> wrote:

> As I recall, proxy-arp behavior is proven by looking in the local host arp
> cache and finding entries for foreign ip’s mapped to the default gateway’s
> mac address.  If that is still occurring, then it would seem that proxy arp
> functionality is still working and you can move on to tshooting something
> beyond that… like what is the upstream def gw/evpn pe doing with those
> packets
>
> Aaron
>
> > On Dec 6, 2023, at 6:16 AM, Jackson, William via juniper-nsp <
> juniper-nsp at puck.nether.net> wrote:
> >
> > Hi
> >
> > Maybe somebody knows the answer to this one:
> >
> > We migrated some customers to an EVPN domain away from a legacy node
> that used proxy-arp on its L3 interface.
> >
> > The downstream clients have some funky routing and they are relying on
> proxy-arp to resolve an offnet address (don't ask me why for our sanities
> sake)!
> >
> > We have a implemented EVPN bridge domain with the following config on MX
> PE nodes running 21.1 code.
> >
> > instance-type virtual-switch;
> > protocols {
> >    evpn {
> >        encapsulation mpls;
> >        default-gateway do-not-advertise;
> >        extended-vlan-list [ 250  ];
> >    }
> > }
> > bridge-domains {
> >    250 {
> >        domain-type bridge;
> >        vlan-id 250;
> >        interface ae68.250;
> >        routing-interface irb.25068;
> >    }
> > }
> >
> > interfaces irb.25068 {
> >  proxy-arp;
> >  family inet {
> >      address 172.23.248.1/22;
> >  }
> >  mac 00:aa:dd:00:00:68;
> > }
> >
> > This irb is in a L3VPN instance.
> >
> > Now the documentation states that proxy-arp and arp-suppression is on by
> default yet these clients cant reach the offnet host with or without the
> "proxy-arp" command on the irb.
> >
> > Any ideas?
> >
> > thanks
> > _______________________________________________
> > juniper-nsp mailing list juniper-nsp at puck.nether.net
> > https://puck.nether.net/mailman/listinfo/juniper-nsp
>
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