100% Packet Loss in a site-to-site but Network Route is fine showing hops between the agent PCs

[GeraldC1]

site-to-site 100% packet loss (UDP) (but Network Route connecting fine (ICMP)) due to inbound UDP blocked by Windows Firewall on Agent PCs?

[GeraldC1 · Accepted solution]

Here is a short video on this 100% packet loss scenario.

There is obviously good ICMP connectivity because the Network Route is looking good. It's just that the Packet Loss is showing 100% which means that the RTT (Round Trip Time Latency), Jitter and Out of Order stats are all invalid (and are all 0 when they are invalid) because the 100% packet loss in a site-to-site assessment means that the UDP on port 50001, 50002 etc is not getting through or not coming back.

Summary 

• How to troubleshoot 100% Packet Loss in UC Assessor
  site to site assessment.
• Packet Loss 100%
  Burst Packet Loss 100%
  Jitter, RTT, Out of Order: all 0% (invalid)
• Reason: UDP connection failing between agents
• Network Route good
• Reason: ICMP connection is successul between agents

Common Causes
- network firewall?
- Windows Firewall on the Agent PCs?
- Anti-virus on Agent PCs?