Apply a firewall filter to count packets from 8.8.8.8 and apply it in input direction on that interface
Sample config:
set firewall family inet filter Count-ICMP term 1 from destination-address 8.8.8.8/32
set firewall family inet filter Count-ICMP term 1 from protocol icmp
set firewall family inet filter Count-ICMP term 1 then count ICMP-OUT
set firewall family inet filter Count-ICMP term 1 then accept
set firewall family inet filter Count-ICMP term 2 from source-address 8.8.8.8/32
set firewall family inet filter Count-ICMP term 2 from protocol icmp
set firewall family inet filter Count-ICMP term 2 then count ICMP-IN
set firewall family inet filter Count-ICMP term 2 then accept
set firewall family inet filter Count-ICMP term 3 then accept
Apply this filter on input and output direction on corresponding interface
set interfaces ge-0/0/0 unit 0 family inet filter input Count-ICMP
set interfaces ge-0/0/0 unit 0 family inet filter output Count-ICMP
Commit the changes, initiate the ping and use below counter to check if the packets come back to SRX
root@srx> show firewall filter Count-ICMP
Filter: Count-ICMP
Counters:
Name Bytes Packets
ICMP-IN 0 0
ICMP-OUT 0 0