Testing MTU With Ping and the DF Bit
Find the path MTU with nothing but ping, from Linux and IOS XE, against a real 1400-byte link. The 28-byte math and the PMTUD black holes that hang TCP.
5 min read
Cisco
2 posts
Cisco Extended Ping and Response Characters Explained
Source interfaces, the DF bit, repeat counts, and the response characters (! . U M) that tell you exactly what failed. Extended ping on Cisco IOS XE, captured live.
5 min read