A customer is having issue with our system and after investigating and analyzing tcp traffic with tcpdump, I noticed that fragmented packets were not received by our cloud server (OVH).
I did some tests:
- Changed the cloud server address to our old one (Azure), and everything was working fine!
- Reverted back the server to production server and again, fragmented packets are not received.
- Modified the MTU from 1500 to 1492 on the customer system, and now it's working perfectly!
Why MTU size is affecting communication for one server and not the other? This customer is using verizon hotspot, I saw something similar at another customer using Satellite connection (Xplornet)