[BUG] Persistent ECONNRESET on home network (VDSL), works fine on mobile hotspot — macOS

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

[BUG] Persistent ECONNRESET on home network (VDSL), works fine on mobile hotspot — macOS

What's Wrong?

Claude Code fails almost every turn on my home network with:

Connection dropped (ECONNRESET) · Retrying in Xs · attempt N/10

Retries exhaust all 10 attempts without recovering. Killing the process and restarting does not help — same error immediately on relaunch. The issue is not intermittent noise; it happens consistently on this network.

Environment

• Claude Code version: 2.1.241 (native install, ~/.local/bin/claude)
• OS: macOS (MacBook Air)
• Network: Home VDSL line via D-Link Epicentro DVA-5592 (TIM), downstream ~77 Mbps, upstream ~21.6 Mbps
• No VPN, no proxy configured

Troubleshooting already performed (all failed to resolve it)

• curl -v https://api.anthropic.com completes a full TLS 1.3 handshake, ALPN h2 accepted, clean HTTP/2 404 from Cloudflare — confirms basic connectivity, DNS, and TLS are healthy
• Killed all Claude processes (pkill -9 -f claude) and relaunched — same error immediately
• Found and removed a leftover duplicate npm global install (@anthropic-ai/claude-code at /usr/local/bin/claude) alongside the native install — no change
• Full logout + config reset (moved ~/.claude aside, fresh login) — same error immediately
• Confirmed already on latest version (claude update → "up to date")
• Disabled SIP ALG on the router — no change (re-enabled afterward, not related to the actual fix)
• IPv6 already disabled on the router — not a factor
• Temporarily reduced net.inet.tcp.sendspace from 131072 to 65536 (suspected router upload-buffer overflow, per a known writeup with an identical symptom pattern on VDSL) — no change (reverted afterward)

Key diagnostic: works on mobile hotspot

Switching the Mac to a phone's mobile hotspot, with everything else identical (same Mac, same Claude Code install/config, same time), Claude Code connects and works normally with no ECONNRESET.

This isolates the problem to something specific about the home network path (this router/ISP), but none of the standard local mitigations (ALG, IPv6, TCP buffer tuning, cache/install reset) resolved it — suggesting it may be a streaming-connection-specific interaction (long-lived HTTP/2 request) rather than a general connectivity issue, similar to other reports of Cloudflare edge / streaming connections being reset while short requests via curl succeed.

Expected behavior

Claude Code should connect and complete turns reliably on this network, the same way curl and short requests do, and the same way it does over mobile hotspot.

What Should Happen?

Claude Code should connect and complete turns reliably on this network, the same way curl and short requests do, and the same way it does over mobile hotspot.

Error Messages/Logs

Steps to Reproduce

1. Connect Mac to home network (VDSL via D-Link Epicentro DVA-5592, TIM, ~77 Mbps down / ~21.6 Mbps up)
2. Launch Claude Code (claude) from a project directory
3. Send any prompt, especially one requiring streamed output (e.g. reading/writing a file)
4. Observe "Connection dropped (ECONNRESET) · Retrying in Xs · attempt N/10" — retries exhaust without recovering
5. Switch to a mobile hotspot with everything else identical — same prompt completes normally with no error

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.241

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_