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当前系统环境：CentOS 7 x64. dotnet 2.0.
不管是
ServicePointManager.ServerCertificateValidationCallback = (a, b, c, d) => true;
还是：
HttpClient httpClient = new HttpClient(new HttpClientHandler() {ServerCertificateCustomValidationCallback = (a, b, c, d) => true });
都会发生错误：
错误信息大致如下：
(The handler does not support custom handling of certificates with this combination of libcurl (7.29.0) and its SSL backend (“NSS/3.28.4”).) —> System.PlatformNotSupportedException: The handler does not support custom handling of certificates with this combination of libcurl (7.29.0) and its SSL backend (“NSS/3.28.4”).
at System.Net.Http.CurlHandler.SslProvider.SetSslOptionsForUnsupportedBackend(EasyRequest easy, ClientCertificateProvider certProvider)
at System.Net.Http.CurlHandler.SslProvider.SetSslOptions(EasyRequest easy, ClientCertificateOption clientCertOption)
解决方案：
# yum update（可选）
# yum install openssl-devel gcc #安装 openssl 和 gcc
# 安装指定版本的 curl
# wget https://curl.haxx.se/download/curl-7.55.1.tar.gz
# tar -zxf curl-7.55.1.tar.gz
# cd curl-7.55.1
# ./configure –prefix=/usr/local/curl/ –without-nss –with-ssl=/usr/local/ssl/
# make
# make install
# 备份原来的 curl
mv /usr/bin/curl /usr/bin/curl.bak
# 将安装的 curl 创建软连
ln -s /usr/local/curl/bin/curl /usr/bin/curl
# curl –version
# 差不多输出下面的内容
#curl 7.55.1 (x86_64-pc-linux-gnu) libcurl/7.55.1 OpenSSL/1.0.2k zlib/1.2.7
# 增加 lib 搜索目录
# vi /etc/ld.so.conf
# 增加
# /usr/local/curl/lib
# cat /etc/ld.so.conf
差不多下面这样子
#
include ld.so.conf.d/*.conf
/usr/local/curl/lib
# 重新 load 配置
# ldconfig
