use LWP::UserAgent; 
use IO::Socket::SSL;
use strict;
use warnings;

my $ua  = LWP::UserAgent->new (); 
$ua->ssl_opts(
    verify_mode   => SSL_VERIFY_PEER,
    verify_hostname => 0,                # Überprüfung des Zertifikats abschalten
);
my $req = HTTP::Request->new(
    GET => 'https://api.flickr.com/services/rest/?method=flickr.auth.getFrob&api_key=df2c4935d4a2dedb9e618f400e808b4c&format=rest&auth_token=72157651265610617-7929d0e254995744&api_sig=8b0edba90343f1593dcb14ad39ce07d7'
);
my $res = $ua->request($req);
print $res->headers_as_string;

Cache-Control: private
Connection: close
Date: Fri, 03 Apr 2015 13:31:58 GMT
Via: http/1.1 fts125.flickr.bf1.yahoo.com (ApacheTrafficServer/4.0.2 [cMsSf ]), http/1.1 r12.ycpi.dea.yahoo.net (ApacheTrafficServer [cMsSf ])
Age: 0
Server: ATS
Vary: Accept-Encoding
Content-Length: 120
Content-Type: text/xml; charset=utf-8
Client-Date: Fri, 03 Apr 2015 13:31:55 GMT
Client-Peer: 188.125.93.39:443
Client-Response-Num: 1
Client-SSL-Cert-Issuer: /C=US/O=VeriSign, Inc./OU=VeriSign Trust Network/OU=Terms of use at https://www.verisign.com/rpa (c)10/CN=VeriSign Class 3 Secure Server CA - G3
Client-SSL-Cert-Subject: /C=US/ST=California/L=Sunnyvale/O=Yahoo Inc./CN=www.yahoo.com
Client-SSL-Cipher: ECDHE-RSA-AES128-SHA256
Client-SSL-Socket-Class: IO::Socket::SSL
Client-SSL-Warning: Peer certificate not verified
P3P: policyref="http://info.yahoo.com/w3c/p3p.xml", CP="CAO DSP COR CUR ADM DEV TAI PSA PSD IVAi IVDi CONi TELo OTPi OUR DELi SAMi OTRi UNRi PUBi IND PHY ONL UNI PUR FIN COM NAV INT DEM CNT STA POL HEA PRE LOC GOV"
Strict-Transport-Security: max-age=259200
X-Robots-Tag: noindex
X-Served-By: www56.flickr.bf1.yahoo.com