Description


When the WAN path goes down, multiple ICMP error messages are observed:

ICMP Type 11 – Time Exceeded (TTL expired in transit)


Symptoms

Source IP: x.x.x.x 

Destination IP: y.y.y.y 

Protocol: ICMP  

Info: Time-to-live exceeded (Time to live exceeded in transit)

Solution


The ICMP TTL-expired messages are:


Sourced from the ISP gateway IP: x.x.x.x

Received by the local WAN IP: y.y.y.y


This indicates that packets are exceeding the hop limit within the ISP network before reaching the destination.


Modification History

2026-02-11 : Article Created