What means ' CONNECT xyz.xyz.xyz.xyz:25 HTTP/1.1 ' in my apache protocol?

From: Stefan (c-x-b@web.de)
Date: 04/10/03 

From: "Stefan" <c-x-b@web.de>
Date: Thu, 10 Apr 2003 18:11:51 +0200

Hi @all,

What means ' CONNECT xyz.xyz.xyz.xyz:25 HTTP/1.1 ' in my apache protocol?
And WHY didn't I have an ERROR in my error log???

All entry (from one ip) in my access_log are:

aaa.bbb.ccc.ddd - - [10/Apr/2003:15:35:58 +0200] "\x04\x01" -
aaa.bbb.ccc.ddd - - [10/Apr/2003:15:36:19 +0200] "\x05\x01" -
aaa.bbb.ccc.ddd - - [10/Apr/2003:15:36:20 +0200] "CONNECT xyz.xyz.xyz.xyz:25
HTTP/1.1"

Can anybody explain all the lines to me?

In my error_log was just:
[date] [error] [client aaa.bbb.ccc.ddd] Invalid method in request \x04\x01
[date] [error] [client aaa.bbb.ccc.ddd] Invalid method in request \x05\x01

But why is the CONNECT command not mentioned here?

Bye and thanks a lot!
    Stefan