SNMP walk doesn't show all the ARP table entries for all routing instances (RIs).

• This is the ARP table in the SRX:

root@srx-01> show arp

MAC Address    Address     Name           Interface        Flags

30:b6:4f:2d:96:c2 10.0.0.2       10.0.0.2            ge-0/0/2.0       none

00:00:5e:00:01:07 10.15.241.129  10.15.241.129       ge-0/0/0.0       none

d0:07:ca:58:8b:a0 10.15.241.130  10.15.241.130       ge-0/0/0.0       none

d0:07:ca:58:22:a0 10.15.241.131  10.15.241.131       ge-0/0/0.0       none

ec:13:db:c7:bd:88 10.15.241.158  10.15.241.158       ge-0/0/0.0       none

Total entries: 5

• And this is the SNMP walk:

user@lnx-server:~$ snmpwalk -v3 -l noAuthNoPriv -u NOAUTH -n VPN 10.15.241.148 .1.3.6.1.2.1.4.35.1

iso.3.6.1.2.1.4.35.1.4.525.1.4.10.15.241.129 = Hex-STRING: 00 00 5E 00 01 07

iso.3.6.1.2.1.4.35.1.4.525.1.4.10.15.241.130 = Hex-STRING: D0 07 CA 58 8B A0

iso.3.6.1.2.1.4.35.1.4.525.1.4.10.15.241.131 = Hex-STRING: D0 07 CA 58 22 A0

iso.3.6.1.2.1.4.35.1.4.525.1.4.10.15.241.148 = Hex-STRING: EC 13 DB DE 8D 00

iso.3.6.1.2.1.4.35.1.4.525.1.4.10.15.241.158 = Hex-STRING: EC 13 DB C7 BD 88

iso.3.6.1.2.1.4.35.1.5.525.1.4.10.15.241.129 = Timeticks: (85373639) 9 days, 21:08:56.39

iso.3.6.1.2.1.4.35.1.5.525.1.4.10.15.241.130 = Timeticks: (85371276) 9 days, 21:08:32.76

iso.3.6.1.2.1.4.35.1.5.525.1.4.10.15.241.131 = Timeticks: (85359511) 9 days, 21:06:35.11

iso.3.6.1.2.1.4.35.1.5.525.1.4.10.15.241.148 = Timeticks: (12546) 0:02:05.46

iso.3.6.1.2.1.4.35.1.5.525.1.4.10.15.241.158 = Timeticks: (85376800) 9 days, 21:09:28.00

iso.3.6.1.2.1.4.35.1.6.525.1.4.10.15.241.129 = INTEGER: 3

iso.3.6.1.2.1.4.35.1.6.525.1.4.10.15.241.130 = INTEGER: 3

iso.3.6.1.2.1.4.35.1.6.525.1.4.10.15.241.131 = INTEGER: 3

iso.3.6.1.2.1.4.35.1.6.525.1.4.10.15.241.148 = INTEGER: 4

...

• As you can see, when I run the snmpwalk from VPN RI, the ARP entry for ge-0/0/2 is not showing: 30:b6:4f:2d:96:c2.

The interface being used for the snmpwalk belongs to a custom routing instance, that is why a context with the RI name is being used.

[Junos] How to pull SNMPv3 information from non-default routing-instance

However, that means that the snmpwalk ARP table request will only show the ARP entries for the interfaces belonging to that routing instance. This is by design.