[CentOS] wget certificate issue

wget 으로 https 보안인증서가 있는 서버에 접근시 아래와 같은 에러가 나면서 다운로드가 되지 않습니다.

[root@raspberry log]# wget https://www.example.com/ccs/download.txt
--2023-11-27 08:55:18--  https://www.example.com/ccs/download.txt
Resolving http://www.example.com (http://www.example.com)... 192.168.1.2
Connecting to http://www.example.com (http://www.example.com)|192.168.1.2|:443... connected.
ERROR: cannot verify http://www.example.com's certificate, issued by ‘/C=US/O=Let's Encrypt/CN=R3’:
  Issued certificate has expired.
To connect to http://www.example.com insecurely, use `--no-check-certificate'.

위의 메시지대로 --no-check-certificate 옵션을 줘도 되겠지만 ca-certificates 를 설치하도록 합니다.

[root@raspberry log]# yum -y install ca-certificates
...
================================================================================
 Package            Arch      Version                          Repository  Size
================================================================================
Updating:
 ca-certificates    noarch    2023.2.60_v7.0.306-72.el7_9      updates    923 k

Transaction Summary
================================================================================
Upgrade  1 Package
...
Updated:
  ca-certificates.noarch 0:2023.2.60_v7.0.306-72.el7_9

Complete!

[root@raspberry log]# wget https://www.example.com/ccs/download.txt
--2023-11-27 09:15:40--  https://www.example.com/ccs/download.txt
Resolving http://www.example.com (http://www.example.com)... 192.168.1.2
Connecting to http://www.example.com (http://www.example.com)|192.168.1.2|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 96735 (94K) [text/plain]
Saving to: ‘download.txt’

100%[======================================>] 96,735      --.-K/s   in 0.03s

2023-11-27 09:15:41 (3.13 MB/s) - ‘download.txt’ saved [96735/96735]