Printer communication is blocked as network attack

Hi,

I do have a small LAN at home with about 4-6 computers and a HP Officejet 6500 A scanner/printer/copymachine/fax device (IP address 192.168.178.21). Comodo Firewall blocks the UDP communication from the Officejet as a network attack and I cannot print or scan. As soon as I disable Comodo Firewall I can print and scan via the installed HP software. My notebook has the IP address 192.168.178.31. Communication with the Officejet works via http interface, however, the printer spooler / driver cannot communicate with the printer.

I’ve already added the printer’s IP adrdress to the home network zone in the firewall configuration, still, the UDP communication from the printer to my computer is blocked as a network attack.

How can I configure Comodo Firewall to allow all communications between the HP Officejet and my computer?!?

Thank you!
Cheers,
Lars

[attachment deleted by admin]

Hello Lars Behnke. Under Firewall settings if Block Fragmented IP Traffic is checked then you need to uncheck it.

I have noticed issues with HP printers that like to send fragmented IP packets this is why comodo is blocking the packets because by default, in firewall advanced settings the option to block fragmented IP traffic is enabled, so disable this option to be able to use a network attached printer. You can tell when comodo blocks fragmented packets is when the log shows the source and destination ports are both equal to 0.

Thank you sAyer and futuretech, that solved it. The question now is, how much security do I give up by not blocking fragmented IP packets … ? Because there is no setting or option to accept fragmented IP packets from a specific MAC or IP address, especially if this address is part of the home network …

Thanks again,
Lars

You don’t lose or gain security by having this option disabled/enabled as pretty mush almost all traffic should be sent/received non-fragmented so you should be fine. The help documentation for version 5.x actually states this

A personal computer rarely needs to send or receive fragmented IP packets but some network enabled devices e.g. printers may require fragmented traffic.

Thank you!
Cheers,
Lars