错误信息：
E: Failed to fetch https://packages.sury.org/php/pool/main/p/php-defaults/php-common_96%2b0%7e20250402.56%2bdebian12%7e1.gbp84a5b7_all.deb Temporary failure resolving 'packages.sury.org'
E: Failed to fetch https://packages.sury.org/php/pool/main/p/php8.3/php8.3-bcmath_8.3.20-4%2b0%7e20250414.61%2bdebian12%7e1.gbp1029c4_amd64.deb Could not connect to packages.sury.org:443 (151.101.111.52), connection timed out
E: Failed to fetch https://packages.sury.org/php/pool/main/p/php8.3/php8.3-zip_8.3.20-4%2b0%7e20250414.61%2bdebian12%7e1.gbp1029c4_amd64.deb Unable to connect to packages.sury.org:https:
E: Failed to fetch https://packages.sury.org/php/pool/main/p/php8.3/php8.3-xml_8.3.20-4%2b0%7e20250414.61%2bdebian12%7e1.gbp1029c4_amd64.deb Unable to connect to packages.sury.org:https:
E: Failed to fetch https://packages.sury.org/php/pool/main/p/php8.3/php8.3-readline_8.3.20-4%2b0%7e20250414.61%2bdebian12%7e1.gbp1029c4_amd64.deb Unable to connect to packages.sury.org:https:
E: Failed to fetch https://packages.sury.org/php/pool/main/p/php8.3/php8.3-opcache_8.3.20-4%2b0%7e20250414.61%2bdebian12%7e1.gbp1029c4_amd64.deb Unable to connect to packages.sury.org:https:
E: Failed to fetch https://packages.sury.org/php/pool/main/p/php8.3/php8.3-mysql_8.3.20-4%2b0%7e20250414.61%2bdebian12%7e1.gbp1029c4_amd64.deb Unable to connect to packages.sury.org:https:
E: Failed to fetch https://packages.sury.org/php/pool/main/p/php8.3/php8.3-mbstring_8.3.20-4%2b0%7e20250414.61%2bdebian12%7e1.gbp1029c4_amd64.deb Unable to connect to packages.sury.org:https:
E: Failed to fetch https://packages.sury.org/php/pool/main/p/php8.3/php8.3-intl_8.3.20-4%2b0%7e20250414.61%2bdebian12%7e1.gbp1029c4_amd64.deb Unable to connect to packages.sury.org:https:
E: Failed to fetch https://packages.sury.org/php/pool/main/p/php8.3/php8.3-gd_8.3.20-4%2b0%7e20250414.61%2bdebian12%7e1.gbp1029c4_amd64.deb Unable to connect to packages.sury.org:https:
E: Failed to fetch https://packages.sury.org/php/pool/main/p/php8.3/php8.3-cli_8.3.20-4%2b0%7e20250414.61%2bdebian12%7e1.gbp1029c4_amd64.deb Unable to connect to packages.sury.org:https:
E: Failed to fetch https://packages.sury.org/php/pool/main/p/php8.3/php8.3-fpm_8.3.20-4%2b0%7e20250414.61%2bdebian12%7e1.gbp1029c4_amd64.deb Unable to connect to packages.sury.org:https:
E: Failed to fetch https://packages.sury.org/php/pool/main/p/php8.3/php8.3-curl_8.3.20-4%2b0%7e20250414.61%2bdebian12%7e1.gbp1029c4_amd64.deb Unable to connect to packages.sury.org:https:
E: Failed to fetch https://packages.sury.org/php/pool/main/p/php8.3/php8.3-common_8.3.20-4%2b0%7e20250414.61%2bdebian12%7e1.gbp1029c4_amd64.deb Unable to connect to packages.sury.org:https:
E: Failed to fetch https://packages.sury.org/php/pool/main/p/php-imagick/php8.3-imagick_3.8.0%7erc2-3%2b0%7e20250408.50%2bdebian12%7e1.gbpd16435_amd64.deb Unable to connect to packages.sury.org:https:
E: Failed to fetch https://packages.sury.org/php/pool/main/d/debsuryorg-archive-keyring/debsuryorg-archive-keyring_2025.03.13_all.deb Unable to connect to packages.sury.org:https:
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
问题分析：
这个错误说明 Debian 12 在更新或安装 PHP 包时，无法连接到 packages.sury.org。这是 PHP 的一个常用第三方源（由 Ondřej Surý 提供），经常用于安装更新版本的 PHP。但现在遇到了类似 DNS 解析失败或连接超时的问题。
解决办法：
出现这个问题的原因，大概率是因为packages.sury.org在国内访问不畅，可以使用以下方法尝试解决：
尝试切换服务器DNS，执行/etc/resolv.conf，添加以下内容：
nameserver 8.8.8.8
nameserver 1.1.1.1然后再执行：
sudo apt update
sudo apt upgrade如果还是不能解决，可以那么只能挂代码，或者切换源，不过 sury.org 很少有完整镜像，可能需要手动下载 .deb 包安装。
最后如果都无法解决，可以暂时注释掉 Sury 源。
我是通过修改DNS解决的问题。