[Boto]
debug = 2
num_retries = 1
proxy = random.proxy.com
proxy_port = 8080

True
path /
auth_path /
path2 /
use_proxy
True
**skip_proxy
False**
path3 https://<path changed>/
method:(GET) protocol:(https) host(random.host.com) port(443) path(https://<path changed>/) params({}) headers({}) body()
reply: 'HTTP/1.1 200 Connection established\r\n'
send: 'GET https://<path changed>/ HTTP/1.1\r\nHost: **** \r\nAccept-Encoding: identity\r\nDate: Thu, 05 Dec 2019 13:15:05 GMT\r\nContent-Length: 0\r\nAuthorization: AWS 2*** \r\nUser-Agent: Boto/2.49.0 Python/2.7.13 Linux/4.12.14-95.24-default\r\n\r\n'
reply: 'HTTP/1.1 503 Service Unavailable\r\n'
header: Server: squid
header: Mime-Version: 1.0
header: Date: Thu, 05 Dec 2019 13:15:05 GMT
header: Content-Type: text/html;charset=utf-8
header: Content-Length: 18387
header: X-Squid-Error: ERR_DNS_FAIL 0
header: X-Cache: MISS from swre-prx001-ch-her-4
header: Via: 1.1 swre-prx001-ch-her-4 (squid)
header: Connection: close
send: 'GET https://<path changed>/ HTTP/1.1\r\nHost: **** \r\nAccept-Encoding: identity\r\nDate: Thu, 05 Dec 2019 13:15:05 GMT\r\nContent-Length: 0\r\nAuthorization: AWS 2*** \r\nUser-Agent: Boto/2.49.0 Python/2.7.13 Linux/4.12.14-95.24-default\r\n\r\n'
reply: ''
reply: 'HTTP/1.1 200 Connection established\r\n'
Traceback (most recent call last):
  File "s3.py", line 4, in <module>
    for bucket in conn.get_all_buckets():
  File "/usr/lib/python2.7/site-packages/boto/s3/connection.py", line 443, in get_all_buckets
    response = self.make_request('GET', headers=headers)
  File "/usr/lib/python2.7/site-packages/boto/s3/connection.py", line 675, in make_request
    retry_handler=retry_handler
  File "/usr/lib/python2.7/site-packages/boto/connection.py", line 1080, in make_request
    retry_handler=retry_handler)
  File "/usr/lib/python2.7/site-packages/boto/connection.py", line 1030, in _mexe
    raise BotoServerError(response.status, response.reason, body)
boto.exception.BotoServerError: BotoServerError: 503 Service Unavailable

cat /etc/sysconfig/proxy | grep NO_PROXY
Example: NO_PROXY="www.me.de, do.main, localhost"
NO_PROXY="localhost,127.0.0.1,.expected.domain.com"

cat /etc/sysconfig/proxy | grep NO_PROXY
Example: NO_PROXY="www.me.de, do.main, localhost"
NO_PROXY="localhost, 127.0.0.1, .expected.domain.com"