Here are a couple of special replies when trying to send invalid HTTP requests:
aghaster@debian:~$ telnet 192.168.1.175 8000
Trying 192.168.1.175...
Connected to 192.168.1.175.
Escape character is '^]'.
GET /../ HTTP/1.1
Host: 192.168.1.175
HTTP/1.0 200 OK
cd: 2: can't cd to /web
Expires: Sun, 27 Feb 1972 08:00:00 GMT
Pragma: no-cache
Cache-Control: no-cache
Content-Type: text/html
<html>
<head>
<META HTTP-EQUIV="Pragma" CONTENT="no-cache">
<META HTTP-EQUIV="Expires" CONTENT="-1">
<META HTTP-EQUIV="Content-type" CONTENT="text/html; charset=UTF-8">
<TITLE> 3600-4600 Series</TITLE>
<LINK REL="stylesheet" HREF="/configStyle.css" TYPE="text/css">
</head>
<frameset cols="185,*" framespacing="0" border="0" frameborder="0">
<frame name="left" scrolling="no" target="rtop" src="/cgi-bin/dynamic/left_bar.html">
<frameset rows="120,*,50">
<frame name="rtop" target="rbottom" src="./cgi-bin/dynamic/topbar.html" marginwidth="0" marginheight="0" scrolling="no" noresize>
<frame name="rbottom" src="/cgi-bin/dynamic/status_list.html" scrolling="auto" marginwidth="15" marginheight="10" noresize target="_self">
<frame name="bottombar" target="bottombar" src="./cgi-bin/dynamic/langbar.html" marginwidth="0" marginheight="0" scrolling="no" noresize>
</frameset></frameset>
<noframes>
<body>
<p>This page uses frames, but your browser does not support them.</p>
</body>
</noframes>
</frameset>
</html>
Connection closed by foreign host.
aghaster@debian:~$ telnet 192.168.1.175 8000
Trying 192.168.1.175...
Connected to 192.168.1.175.
Escape character is '^]'.
GET //index.html HTTP/1.1
Host: 192.168.1.175
HTTP/1.1 400 Bad Request
Server: thttpd
Content-Type: text/html
Date: Tue, 04 Apr 2006 03:30:07 GMT
Last-Modified: Tue, 04 Apr 2006 03:30:07 GMT
Accept-Ranges: bytes
Connection: close
booga3!
<HTML>
<HEAD><TITLE>400 Bad Request</TITLE></HEAD>
<BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#2020ff" VLINK="#4040cc">
<H2>400 Bad Request</H2>
Your request has bad syntax or is inherently impossible to satisfy.
Connection closed by foreign host.
aghaster@debian:~$ telnet 192.168.1.175 8000
Trying 192.168.1.175...
Connected to 192.168.1.175.
Escape character is '^]'.
invalid.
UNKNOWN 400 Bad Request
Server: thttpd
Content-Type: text/html
Date: Tue, 04 Apr 2006 03:30:59 GMT
Last-Modified: Tue, 04 Apr 2006 03:30:59 GMT
Accept-Ranges: bytes
Connection: close
<HTML>
<HEAD><TITLE>400 Bad Request</TITLE></HEAD>
<BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#2020ff" VLINK="#4040cc">
<H2>400 Bad Request</H2>
Your request has bad syntax or is inherently impossible to satisfy.
Connection closed by foreign host.
aghaster@debian:~$ telnet 192.168.1.175 8000
Trying 192.168.1.175...
Connected to 192.168.1.175.
Escape character is '^]'.
GET /404.htm HTTP/1.1
Host: 192.168.1.175
HTTP/1.1 404 Not Found
Server: thttpd
Content-Type: text/html
Date: Tue, 04 Apr 2006 03:31:52 GMT
Last-Modified: Tue, 04 Apr 2006 03:31:52 GMT
Accept-Ranges: bytes
Connection: close
<HTML>
<HEAD><TITLE>404 Not Found</TITLE></HEAD>
<BODY BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#2020ff" VLINK="#4040cc">
<H2>404 Not Found</H2>
The requested URL '/404.htm' was not found on this server.
Connection closed by foreign host.
Notice how in the second request I get a "booga3!" error while none of the others get that.
