Ubuntu18.04安装QGIS3.4执行sudo apt-get update遇TLS握手错误求助

Hey there, let's break down the issue you're facing. From what you've shared, you followed the official QGIS install steps but hit a TLS handshake error when running sudo apt-get update. Let's start with the details you provided, then walk through possible causes and fixes.

Your Setup & Error Details #

You updated /etc/apt/sources.list with the QGIS LTR sources:

deb https://qgis.org/ubuntu-ltr bionic main
deb-src https://qgis.org/ubuntu-ltr bionic main

When running sudo apt-get update, you got this error:

ashj@ashj:~/Downloads/LAStools$ sudo apt-get update
[sudo] password for ashj:
Ign:1 https://qgis.org/ubuntu-ltr bionic InRelease
Err:2 https://qgis.org/ubuntu-ltr bionic Release
Could not handshake: An unexpected TLS packet was received. [IP: 10.4.21.120 8080]

Likely Causes & Fixes #

1. Proxy Server Misconfiguration #

First, the IP 10.4.21.120:8080 looks like an internal network proxy. Most often, this error happens when the proxy isn't handling HTTPS traffic correctly.

• Check current proxy settings: Run these commands to see if system-level proxies are set:

  echo $http_proxy $https_proxy
  ls /etc/apt/apt.conf.d/ | grep proxy
  

• Temporarily bypass proxy: If your network allows direct access, try running update without proxy:

  sudo http_proxy= https_proxy= apt-get update
  

• Fix proxy HTTPS support: If you need to use the proxy, configure APT to use it properly. Create/edit /etc/apt/apt.conf.d/99proxy with:

  Acquire::http::Proxy "http://10.4.21.120:8080/";
  Acquire::https::Proxy "http://10.4.21.120:8080/";
  

  Note that we use http:// for the HTTPS proxy—this is intentional, as the proxy itself uses HTTP to forward encrypted HTTPS traffic.

2. TLS Version Incompatibility #

Ubuntu 18.04's APT might be using a TLS version that the QGIS server or your proxy doesn't support.

• Force compatible TLS versions: Edit /etc/apt/apt.conf and add these lines:

  Acquire::https::TLSv1.2 "true";
  Acquire::https::TLSv1.3 "false";
  

  Then re-run sudo apt-get update.

3. Network/Firewall Interference #

Your internal firewall might be intercepting HTTPS traffic (e.g., with a man-in-the-middle certificate) or blocking the QGIS server entirely.

• Test the connection directly: Use curl to diagnose the issue:

  curl -v https://qgis.org/ubuntu-ltr/dists/bionic/Release
  

  If you see certificate errors, you'll need to install your network's root CA certificate:

  sudo cp /path/to/your-ca-cert.pem /usr/local/share/ca-certificates/
  sudo update-ca-certificates
  

4. Try a Different QGIS Source #

Occasionally, the LTR source might have regional accessibility issues. Switch to the standard QGIS repo by updating /etc/apt/sources.list:

deb https://qgis.org/ubuntu bionic main
deb-src https://qgis.org/ubuntu bionic main

Then run sudo apt-get update again.

内容的提问来源于stack exchange，提问作者Ashj