When debugging problems with your HTTP server, access to the raw HTTP request and response headers (and sometimes the entire request and response) can be invaluable. Here we list various tools that can help you see, at minimum, the HTTP response headers sent by the server, and sometimes also request headers and body content.
- livehttpheaders for Mozilla Firefox
- firebug for Mozilla Firefox
- Microsoft Fiddler HTTP Debugger
- WireShark network protocol analyser
- Eavesdrop for Mac OS X
Shell
Various HTTP tools that may be available at the unix prompt:
wget -S --spider URL lynx -head -dump URL curl -I URL HEAD URL GET -de URL w3m -dump_head URL siege -g URL
Manually constructing requests
Using any standard telnet client, you can manually interact with an HTTP server and see the headers.
telnet server.example.com 80 HEAD /dir/page.html HTTP/1.1 Host: server.example.com
Press enter twice at the end.
Tracing headers over SSL
The openssl command can be used to open an SSL connection over which normal HTTP requests can be entered.
openssl s_client -connect secure.example.com:443 .. lots and lots of output .. HEAD / HTTP/1.1 Host: secure.example.com
Press enter twice at the end.
Alternatively, ssldump and wireshark can use the private key file to decrypt live or recorded SSL traffic.