Check the ARP tables on both ends (show arp no-resolve interface ge-0/0/0.0). If they cannot see each other, you have a connectivity issue.
Both units are misconfigured, but equally so, so it should work. In the drawing, you have 172.16.0.1/29, but both units have a /24 mask. This is not the end of the world normally, but if you do have other interfaces with overlapping subnets (using anything else in the 172.16.0.x range), one of the units may be confused.
Do you have a policy that allows the traffic? Normally, traffic going to the SRX is controlled with host-inbound-traffic system-services and protocols, so that shouldn't be the issue. Traffic from the SRX itself (ping in the CLI for instance) is permitted by default. One way to control this better is to use the junos-host security zone. This special zone controls what goes to and comes from the SRX itself. Just like having a policy "from-zone trust to-zone untrust" or similar, you can use for instance the combination "from-zone untrust to-zone junos-host".
https://supportportal.juniper.net/s/article/SRX-Configuration-Example-How-to-limit-self-traffic-using-Security-Policies
One last thing to check is if you have an input filter on interface lo0:
show interfaces lo0
If no filters are configured, you're fine. They are used as a last resort filter mechanism to the RE/CPU of the SRX.
When you're totally stuck, boot up a PC and set the IP of the Cisco on it and connect the PC to the SRX. Now test the ping, ARP etc. If all is good, set the IP of the SRX on the PC and connect it to the Cisco.
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Original Message:
Sent: 10-31-2023 18:49
From: Anonymous
Subject: SRX cannot ping it's Gateway
This message was posted by a user wishing to remain anonymous
Hi Everyone,
I am new to SRX. Looking forward for your help.
I have setup a Lab where there is an IOS device and an SRX with point to point IP
SRX - 172.16.0.2/24
Cisco Router - 172.16.0.1/24
I cannot ping the SRX's IP when trying it to the cisco router.
Here are the configurations:
Cisco Router
interface GigabitEthernet0/1
ip address 172.16.0.1 255.255.255.0
duplex auto
speed auto
SRX
set security zones security-zone untrust interfaces ge-0/0/0.0 host-inbound-traffic system-services all
set security zones security-zone untrust interfaces ge-0/0/0.0 host-inbound-traffic protocols all
set interfaces ge-0/0/0 unit 0 family inet address 172.16.0.2/24
Looking forward for your response. Thanks