This is the retired Shane Killen personal blog, an IT technical blog about configs and topics related to the Network and Security Engineer working with Cisco, Brocade, Check Point, and Palo Alto and Sonicwall. I hope this blog serves you well. -- May The Lord bless you and keep you. May He shine His face upon you, and bring you peace.
Friday, September 25, 2020
Wednesday, September 23, 2020
Can You Ping To A Certain Port Number?
I had a phone conversation today with someone who said that they thought that they could ping to a certain port number. I was walking them through using telnet to see if a port was open, when that statement was made. Thats the quick way to see if a port is open, to just telnet to that port and see if you get a blinking light. Easy enough, but can you ping to a certain port at the destination end?
Quick answer, No. Here is why:
Notice above how there is not port number under layer 4 (Internet Control Message Protocol). You can see Im pinging 220.127.116.11. But you dont see any port number involved.
Now, lets look at a UDP packet:
At layer 4, you do see port numbers. Specifically a source and destination port number. Same for TCP, but not ICMP.
Always prove with a packet capture.