Talk:Server.pl

Here are some directives Apache uses when it deals with IE clients:

SetEnvIf User-Agent ".*MSIE.*" \

nokeepalive ssl-unclean-shutdown \
downgrade-1.0 force-response-1.0

Might give a clue to it's little quirks.

--Rob 09:44, 16 Feb 2006 (NZDT)

Currently HTTP authentication is just base64 encoded username:password which is basically just plain text, so the password can easily be discovered.

• Using MD5 with HTTP Authentication
• RFC2617
• MS ActiveDirectory, but lots of MD5 header info

1. Bugs & Notes

1. 1. Port-binding bug

• This may be due to going directly into init.d rather than inetd --Nad 09:34, 28 Mar 2006 (NZST)

---

• Socket can't bind to port for a minute or so after peer stops. Shutting it officially, blocking, autoflush don't work.

netstat -tupl and lsof -i 1729

shows that the port is freed immediately, but it still won't bind until after the delay.

• Note: server.pl now keeps retrying every 10sec instead of dying Nad 23:29, 16 Feb 2006 (NZDT)
  • Some PERL socket info here
  • PERL proxy-server code - good socket example
  • Peter's Perl Examples - Good socket and other examples

1. 1. HTTP-Response issue

• Using PHP's fsockopen() I've made a workaround for now, by making a request, but not doing a corresponding fgets() which is the one that won't return. --Nad 09:34, 28 Mar 2006 (NZST)
• It seems to be an HTTP/1.0 problem (both wget and PHP's fopen-wrappers use HTTP/1.0)
• Actually, it turns out it does return, but only after a long timeout (another clue!)

---

For some reason certain clients cannot receive a the content from the peer. The headers are received, but then the client times-out waiting for the content.

But this is odd because the code sends the entire header and message in one go...?!?!

The problem is that one of the clients that fails is the one used by the fopen-wrappers in PHP!

Here's what happens when we request from the peer using wget which is also one of the failing clients:

closet:/home/nad# wget http://localhost:1729
--13:50:01--  http://localhost:1729/
           => `index.html'
Resolving localhost... 127.0.0.1
Connecting to localhost[127.0.0.1]:1729... connected.
HTTP request sent, awaiting response... 200 OK
Length: 3,744 [text/html]

 0% [                                 ] 0   --.--K/s

As you can see it must have retreived the headers to know the Content-Type and Content-Length, and is now waiting for the content, not more headers - but why is it waiting when the peer code sends the whole headers+message in one go?

It works fine for curl, and Rob used:

curl -vi http://organicdesign.co.nz:1729 --trace-ascii /dev/tty

to obtain the results listed below (the data has been omitted for brevity). I've commented some different lines to show that those differences have been tested and are not the issue...

== Info: About to connect() to organicdesign.co.nz port 1729
== Info:   Trying 58.28.135.7... == Info: connected
== Info: Connected to organicdesign.co.nz (58.28.135.7) port 1729
=> Send header, 181 bytes (0xb5)
0000: GET / HTTP/1.1
0010: User-Agent: curl/7.13.2 (i386-pc-linux-gnu) libcurl/7.13.2 OpenS
0050: SL/0.9.7e zlib/1.2.2 libidn/0.5.13
0074: Host: organicdesign.co.nz:1729
0094: Pragma: no-cache
00a6: Accept: */*
00b3: 
<= Recv header, 17 bytes (0x11)
0000: HTTP/1.1 200 OK
<= Recv header, 38 bytes (0x26)
0000: Date: Mon, 27 Mar 2006 11:57:45 NZST           // HTTP1.1 insists on GMT, but that didn't fix it
<= Recv header, 15 bytes (0xf)
0000: Server: wikid
<= Recv header, 22 bytes (0x16)
0000: Content-Length: 3744
<= Recv header, 46 bytes (0x2e)
0000: Content-Disposition: inline;filename=Gir.swf   // removing this header didn't fix it
<= Recv header, 19 bytes (0x13)
0000: Connection: close                              // this has been removed now giving "left intact"
<= Recv header, 25 bytes (0x19)
0000: Content-Type: text/html
<= Recv data, 1264 bytes (0x4f0)
============================ DATA ============================
== Info: Connection #0 to host organicdesign.co.nz left intact    // added manually since it gives this now
== Info: Closing connection #0

An here are the headers returned from another site which works fine from wget:

== Info: About to connect() to www.cs.auckland.ac.nz port 80
== Info:   Trying 130.216.33.106... == Info: connected
== Info: Connected to www.cs.auckland.ac.nz (130.216.33.106) port 80
=> Send header, 178 bytes (0xb2)
0000: GET / HTTP/1.1
0010: User-Agent: curl/7.13.2 (i386-pc-linux-gnu) libcurl/7.13.2 OpenS
0050: SL/0.9.7e zlib/1.2.2 libidn/0.5.13
0074: Host: www.cs.auckland.ac.nz
0091: Pragma: no-cache
00a3: Accept: */*
00b0: 
<= Recv header, 17 bytes (0x11)
0000: HTTP/1.1 200 OK
<= Recv header, 37 bytes (0x25)
0000: Date: Sun, 26 Mar 2006 23:58:03 GMT
<= Recv header, 30 bytes (0x1e)
0000: Server: Apache/1.3.33 (Unix)
<= Recv header, 30 bytes (0x1e)
0000: Cache-Control: max-age=18000
<= Recv header, 40 bytes (0x28)
0000: Expires: Mon, 27 Mar 2006 04:58:03 GMT
<= Recv header, 28 bytes (0x1c)
0000: Transfer-Encoding: chunked
<= Recv header, 25 bytes (0x19)
0000: Content-Type: text/html
<= Recv data, 2687 bytes (0xa7f)
============================ DATA ============================
== Info: Connection #0 to host www.cs.auckland.ac.nz left intact
== Info: Closing connection #0

---

I made server.pl dump all input to the log before splitting into message etc, here's what curl gives:

Mon Mar 27 16:04:31 2006 : [serverStart]	== DATA STARTS ==
Mon Mar 27 16:04:31 2006 : [serverStart]	GET / HTTP/1.1
User-Agent: curl/7.13.2 (i386-pc-linux-gnu) libcurl/7.13.2 OpenSSL/0.9.7e zlib/1.2.2 libidn/0.5.13
Host: organicdesign.co.nz:1729
Pragma: no-cache
Accept: */*


Mon Mar 27 16:04:31 2006 : [serverStart]	== DATA ENDS ==
Mon Mar 27 16:04:31 2006 : [serverStart]	Gir() requested
Mon Mar 27 16:04:31 2006 : [serverStart]	Stream5 disconnected.

...and here's what wget gives:

Mon Mar 27 16:08:12 2006 : [serverStart]	== DATA STARTS ==
Mon Mar 27 16:08:12 2006 : [serverStart]	GET / HTTP/1.0
User-Agent: Wget/1.9.1
Host: localhost:1729
Accept: */*
Connection: Keep-Alive


Mon Mar 27 16:08:12 2006 : [serverStart]	== DATA ENDS ==
Mon Mar 27 16:08:12 2006 : [serverStart]	Gir() requested