Hey everyone! I'm troubleshooting an issue with a web application that serves HTTPS traffic on port 2443. Everything works great across all VLANs except for one, where clients are facing an `ERR_SSL_PROTOCOL_ERROR`. I'm able to ping the server from that VLAN, and tests like curl show a connection but result in an empty reply. My developer has tried different SSL settings without any luck. I'm curious why this seems like an application issue when it works fine for other VLANs. Could it be related to VLAN ACLs, switch configurations, or something else? Any advice would be super helpful!
3 Answers
You might want to consider that port 2443 is non-standard for HTTPS and could be getting blocked somewhere. Look into your upstream ACLs or any possible firewalls that might be interfering with the traffic. Also, ensure that the traffic isn’t getting dropped due to an implicit deny rule.
First off, check for any devices that might be doing deep packet inspection on the traffic from that VLAN. If you’ve tested with different devices across VLANs, it’s possible that the issue lies with the specific device you're using for the testing on the affected VLAN.
I agree with the others; it sounds like a network issue pretending to be an app problem. If you can set up a testing machine in the same switch and VLAN, that would help rule out the app. If you get the same error, it might point to a mismatch in TLS versions or ciphers, especially with the new security updates. Trying a different cipher or checking the curl output with verbose logging could give you more insights.
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