Proxy ARP between Ubuntu and Raspberry

I have a not so new PC on which I installed Ubuntu 24.04 LTS. It does not have WiFi connectivity, and I do not have a wired internet connection. Therefore, I would like to endow it an internet access through a Raspberry Pi, which can connect to a WiFi hotspot. I would connect the PC with the Raspberry by means of Ethernet. The Raspberry has Raspberry Pi OS Bookworm, and it gets the IP dynamically on the wlan0 interface. Instead, on its Ethernet eth0 interface I set the static IP 172.16.10.105 and subnet mask 255.255.255.0. On the other hand, the Ethernet interface enp4s0 on the old PC is set with the static IP 172.16.10.104, subnet mask 255.255.255.0, and gateway 172.16.10.105 (this is the IP of the eth0 interface of the Raspberry). The eth0 interface of the Raspberry and the enp4s0 of the Ubuntu PC are connected through an Ethernet cable. To realize the bridge to share the internet access, on the Raspberry I enabled the IP forwarding by uncommenting the line net.ipv4.ip_forward=1 in the file /etc/sysctl.conf, and I used parprouted as follows: sudo parprouted -d eth0 wlan0 To monitor what happens on the eth0 interface of the Raspberry, I ran: sudo tcpdump --interface eth0 The ping from the old PC to the Raspberry is ok, but when I try to access internet from the old PC (as an example, with curl https://stackoverflow.com ) it fails, and both tcpdump and parprouted seem to indicate that the Raspberry did not receive anything. Here you can find the output of both tcpdump and parprouted (I just substituted a few IP and MAC addresses as a caution): log files They recorded the activity due to the ping, but they recorded nothing when I run the curl command. What am I missing? Thanks a lot.