I'm not sure I follow the configuration but it looks like the following.
You have the loopback on the interface facing the client and you want to proxy arp for a device on this interface.
SRX will proxy arp on an interface that includes a subnet for traffic being processed by nat and security policy rules, not for outside devices.
------------------------------
Steve Puluka BSEET - Juniper Ambassador
IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP - Retired)
http://puluka.com/home------------------------------
Original Message:
Sent: 07-09-2022 04:12
From: Vlad Sol
Subject: proxy-arp on 19.4R3-S8.6
Hi, all.
HW: MX104, 19.4R3-S8.6
Interface configuration:
x@router0> show configuration interfaces ge-0/0/4.1031
proxy-arp;
vlan-id 1031;
family inet {
unnumbered-address lo0.1;
}
Route table:
Internet.inet.0: 856733 destinations, 1583377 routes (856733 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both
1.2.3.8/29 *[BGP/170] 1d 20:29:49, localpref 100, from x.x.x.x
...
x@router0> monitor traffic no-resolve interface ge-0/0/4.1031
verbose output suppressed, use <detail> or <extensive> for full protocol decode
Address resolution is OFF.
Listening on ge-0/0/4.1031, capture size 96 bytes
10:54:17.148597 In arp who-has 1.2.3.11 tell 1.2.4.147
10:54:18.166338 In arp who-has 1.2.3.11 tell 1.2.4.147
10:54:19.190364 In arp who-has 1.2.3.11 tell 1.2.4.147
10:55:17.118386 In arp who-has 1.2.3.11 tell 1.2.4.147
10:55:18.135908 In arp who-has 1.2.3.11 tell 1.2.4.147
10:55:19.159885 In arp who-has 1.2.3.11 tell 1.2.4.147
The problem is that the router does not respond to arp requests coming from client's side (client ip, that connected to ge-0/0/4.1031 is 1.2.4.147/20).
proxy-arp is set (tried to set unrestricted, but nothing changes). The route to network 1.2.3.8/29 is in the routing table. What could be the problem?