Hacker News new | ask | show | jobs
by deaps 2804 days ago
A ping is very much different. A ping is (typically) simply an ICMP Echo Request, (not TCP, thus no TLS, etc). The receiving device, if accepting echo requests and configured to reply with echo replies, then responds with an ICMP Echo Reply - or some device in the middle (or the device itself could respond with an ICMP unreachable, or some other response - or quite simply drop the ICMP Echo Request entirely and silently).

*Edited an incorrect UDP reference out based on the below comment.
1 comments
gear54rus 2804 days ago
If I'm not mistaken, its not UDP, it's ICMP, like you said
link
deaps 2804 days ago
Ahh yeah - good call. Totally different protocol. I guess ICMP more closely resembles UDP at the end of the day, but you're absolutely right. I edited out the incorrect UDP reference so that a person reading for the first time will not get misled. Thanks!
link
e12e 2802 days ago
Which is also why some poorly configured network devices firewalls will eat pings - if they for example whitelist tcp and udp protocols and drop everything else (yes, that's a bad idea).

https://security.stackexchange.com/questions/22711/is-it-a-b...

link