Forum Discussion

Tutor

Dec 11, 2025

Solved

CAX80 v5.1.1.8 Firewall Blocking HTTPS API Traffic - DMZ Confirmed

Hi all, I'm experiencing a firewall bug on my CAX80 (firmware v5.1.1.8) that's blocking HTTPS API calls to legitimate services (specifically api.anthropic.com for Claude AI/Claude Code). Symp...

cax80

FURRYe38
Dec 11, 2025
What region are you located?

Who is your ISP?

Is SIP ALG enabled on the modem?

Something to contact NG about.

Something to contact NG support about.

Look up what ports are used by your API traffic and input that in to Port Forwarding or Port Triggering configuration. If you try this, be sure to disable uPnP before hand.

CrimpOn

Guru - Experienced User

Dec 12, 2025

Confused. On Spectrum in the US, I entered https://api.anthropic.com into the Edge browser and got this:

Same results with other browsers. (Brave, Chrome, Opera, etc.) My guess is that this URL is not supposed to lead to a web page, but rather to a programming interface? (api?)

StephenB
Guru - Experienced User
Dec 12, 2025
CrimpOn wrote:
Confused.

Read this:

https://platform.claude.com/docs/en/api/overview

This is not a web page, it is a RESTful API that allows developers to access cloud-based Claude models from their applications.

FURRYe38 wrote:
Is SIP ALG enabled on the modem?

I don't think this will matter in this situation, but generally it should be disabled.

FURRYe38 wrote:
Look up what ports are used by your API traffic

RESTful APIs use HTTP/HTTPS messages, on the normal ports. HTTPS in this case, so port 443. There is also account authentication, which I believe does a callback on port 54545.

@brief-actuator: Have you tried forwarding these two ports to the PC you are using?

If that doesn't work, I suggest taking a wireshark trace with the PC in the DMZ, and see if there are other ports being used.