Which Icmp Types to Allow?
The Only Essential Icmp Traffic You Need to Allow in and out of Your Firewall Is Type 3 and Type 4. Everything Else Is Either Optional or Should Be Blocked...
The only essential ICMP traffic you need to allow in and out of your firewall is Type 3 and Type 4. Everything else is either optional or should be blocked. Notes: To send ping requests, allow type 8 OUT and type 0 IN.
How many types of ICMP packets can be?
Echo Reply (0), Echo Request (8), Redirect (5), Destination Unreachable (3), Traceroute (30), Time Exceeded (11). Many of these ICMP types have a "code" field.
Must Read
Should I allow all ICMP?
Many network administrators feel that ICMP is a security risk, and should therefore always be blocked at the firewall. It is true that ICMP does have some security issues associated with it, and that a lot of ICMP should be blocked. But this is no reason to block all ICMP traffic!
David Miller brings 15 years of experience in global economics, personal finance strategy, and market dynamics. He specializes in turning complex economic trends into actionable insights for everyday readers.
