Firewall event: blocking ARP protocol communication from printer and laptop

I repeatedly see firewall events on my desktop where ARP communication from the printer (HP Officejet 8600) is blocked. The source and destination IP addresses are identical, both being the printer’s and not the desktop’s ip. Yet the CIS (v6.3) firewall is on my desktop.
Occasionally I also see the same events on my desktop related to ARP communication from my wife’s laptop. Again, the source and destination ip’s are both the laptop’s ip yet I see the blocking on CIS on my desktop.

I am concerned that some normal communication between the printer and desktop might be being blocked.

Is the blocked communication something to worry about or is it part of normal printer communication? How would I prevent this communication from being blocked?

ARP is Address Resolution Protocol. As far as I know, it’s used mostly for mapping MAC addresses to IP addresses on your LAN. I think it’s a little strange that CIS is reporting that it’s “blocking” packets that aren’t addressed to your PC. If your computers can print just fine, I suspect you won’t gain anything from “unblocking” this.

Carl99, not sure if you saw my post a few threads down which I just updated, (see, but I too am experiencing a similar issue. I have a machine (A) that will receive numerous ARP requests from other devices on the same network whenever they connect. I’m curious if you would happen to have cloned the pc’s address receiving the requests to your network router at any time?

When the logs show the source and destination address of the ARP request to be the same then there is nothing to worry about.

Can anyone say why Comodo reports it as a “blocked” packet if the destination address isn’t the address of the PC running Comodo? I can imagine some reasons why this might be, but I’d love to hear what the real thinking is.

FwFan, I’m still trying to figure this out. While cleaning up a roommates (CIS) machine last night (The one mentioned in my Blocked ARP thread causing alerts on one of my (CIS) machines), I placed it along side of mine so I was able to monitor my firewall alerts while attempting to clean up their machine.

Every time their machine was started or restarted, those ARP alerts would show up on my machine, and once they started, they would recur every few seconds until their machine was shut down or restarted.

In response to EricJH

…this makes (me) feel better that I have nothing to worry about, in an intrusion sense, to my machine, but I still wonder, by my machine blocking these ARP requests from reaching their machine, if I am preventing the action causing these requests to not fulfill an important function.

Tomorrow will be network restructure day for me in hopes to resolve this, I’ll report back.