Git Network Errors Troubleshooting: From early EOF to RPC failed

1. Golden Diagnostic Toolkit: Enabling Low-Level Git Tracing

By default, Git outputs only high-level summary messages when a fatal network error occurs, masking HTTP status codes, TLS handshake negotiations, and operating system socket states. Before debugging complex failures, enable verbose trace logs using standard environment variables:

# Inject tracing variables for a single clone command (leaves global config untouched)
GIT_TRACE=1 GIT_TRANSFER_TRACE=1 GIT_CURL_VERBOSE=1 git clone https://github.com/org/repo.git

This prints raw cURL connections, TLS handshakes, and wire frames directly to your terminal:

* Connected to github.com (20.205.243.166) port 443 (#0)
* ALPN, offering h2, http/1.1
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
* Recv failure: Connection reset by peer

2. Issue 1: fatal: early EOF & fatal: index-pack failed

error: RPC failed; result=18, HTTP code = 200
fatal: the remote end hung up unexpectedly
fatal: early EOF
fatal: index-pack failed

Root Cause

This error typically strikes when downloading large Packfiles (often at 90%+ completion). The client expects a specified byte payload (e.g., 600MB), but before the stream completes, intermediate firewalls or upstream servers terminate the TCP connection, resulting in a premature EOF (End Of File). Because bytes are missing, Git’s index-pack validation fails and aborts the clone.

Production-Grade Solutions

• Option A (Immediate): Switch to shallow cloning via our streaming proxy:

  git clone --depth 1 https://ghproxy.icu/https://github.com/org/repo.git

• Option B (Memory Tuning): Adjust Git’s local memory window limits to prevent client-side buffer exhaustion:

  git config --global core.packedGitLimit 512m
  git config --global core.packedGitWindowSize 512m
  git config --global pack.deltaCacheSize 2047m
  git config --global pack.packSizeLimit 2047m
  git config --global pack.windowMemory 2047m

3. Issue 2: RPC failed; curl 56 Recv failure: Connection reset by peer

error: RPC failed; curl 56 Recv failure: Connection reset by peer
fatal: the remote end hung up unexpectedly

Root Cause

1. Cleartext SNI Filtering: Firewalls detect github.com in the TLS Client Hello packet and inject forged TCP RST packets;
2. MTU Path Blackholes: Jumbo frame packets exceeding intermediate network Path MTUs (e.g., > 1492 in PPPoE or VPN tunnels) get dropped without ICMP Fragmentation Needed notifications.

Production-Grade Solutions

• Route via Acceleration Doctor: The proxy terminates client TLS safely, shielding cleartext SNI from intermediate RST injection:

  git clone https://ghproxy.icu/https://github.com/org/repo.git

• Clamp Network MTU: Lower interface MTU to 1420 to prevent packet fragmentation drops:

  # Linux
  sudo ip link set dev eth0 mtu 1420

4. Issue 3: GnuTLS recv error (-110): The TLS connection was non-properly terminated

fatal: unable to access 'https://github.com/org/repo.git/': GnuTLS recv error (-110): The TLS connection was non-properly terminated.

Root Cause

Common on Debian/Ubuntu systems where Git is linked against libcurl-gnutls rather than OpenSSL. GnuTLS handles non-graceful TLS shutdown alerts (close_notify) strictly, triggering fatal exceptions when servers terminate keep-alive connections.

Production-Grade Solutions

• Option A: Reconfigure Git through ghproxy.icu to bypass flaky direct connections;
• Option B: Reinstall cURL with OpenSSL support:

  sudo apt-get update
  sudo apt-get install -y git-core curl libcurl4-openssl-dev

5. Issue 4: Failed to connect to github.com port 443: Connection timed out

fatal: unable to access 'https://github.com/org/repo.git/': Failed to connect to github.com port 443 after 21082 ms: Connection timed out

Root Cause

1. Local DNS poisoning has assigned an unreachable or blocked IP address;
2. Stale Local Proxy Configurations: An earlier HTTP proxy setting (such as 127.0.0.1:7890) remains in ~/.gitconfig, while the local proxy client is no longer running.

Quick Fix

# Check if stale proxies are configured in Git
git config --global --get http.proxy
git config --global --get https.proxy

# Clear stale proxies
git config --global --unset http.proxy
git config --global --unset https.proxy

# Route globally through GitHub Acceleration Doctor
git config --global url."https://ghproxy.icu/https://github.com/".insteadOf "https://github.com/"

6. Diagnostic Matrix: Quick Reference