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The America Online Protocol Revealed

Posted by ryuzaki0 on from the you've-got-something dept.

Gods Misfit writes "The America Online protocol(Connecting, Logging In, Joining Chats, etc..) has remained a mystery for most of its life. The only way one could log into their AOL account was via the AOL software. A few months ago, some people set out to break down the AOL protocol and open the door for alternative America Online software. This document is the result: The AOL Protocol. A sign on example for Visual Basic programmers has been written and is available here." I suspect a fair number of people never try Linux or one of the BSDs because they're moderately happy with AOL as an ISP, and switching OSes would mean switching ISPs at the same time. A shame that AOL doesn't make this kind of information more easily available.

5 of 468 comments (clear)

  1. Re:Illegal Activities? by blakestah · · Score: 5, Informative

    Wouldn't this be considered illegal under the DMCA, since they reverse engineered AOL's proprietary protocol? If AOL had meant for it to be public, then they would have put it out themselves.

    No. Reverse engineering algorithms protected only by copyright is always legal. DMCA makes it illegal to circumvent or reverse engineer copyright protection schemes. There is no evidence anything of the sort has been done.

  2. PDF Format by 1010011010 · · Score: 5, Informative

    Here is the file in PDF, rather than "write" format:

    http://www.flyingbuttmonkeys.com/mirrors/The-AOL-P rotocol.pdf

    --
    Napster-to-go says "Fill and refill your compatible MP3 player", which is a lie. It's not MP3. It's WMA with DRM.
  3. Re:What about mail? by bkocik · · Score: 5, Informative
    A) Reverse engineer the AOL mail protocol so that external programs can at least READ AOL mail (sending, unsending, and AOL custom features are optional)

    It's just a set of IMAP servers. There's no secret about it. If you use Netscape 6.x, it gives you the option to set up an account to retrieve your AOL mail, and it does this by setting you up to do it via IMAP.

    imap.mail.aol.com


    (Yes, I'm an AOL employee)

    --
    -BK
    Chemical Blog
  4. AOL is just a modified PlayNet protocol by jesup · · Score: 5, Informative

    The AOL protocol described is a modification of the old (1984) PlayNet error-correction and data communication protocol I devised (with some input from Steve Bohram, but it was mostly my design based on the Tannenbaum networking book).

    CRC-16 was used because modems (300 baud) didn't have any error correction, and we could use tables to process the data 16 bits at a time without using too much memory or CPU (the servers were 12MHz 68010's).

    Packets all ended in hex 0D because we were using Telenet and Tymnet X25 dial-in pads in line-buffered mode, because we were charged by the packet. We also munged the other fields to avoid 0D (that may be gone now). Also, they were limited to 256 byte lines; thus the length byte instead of something longer.

    Bytes 6 & 7 (which the author doesn't understand) are sequence numbers used in the sliding-window error-correction protocol.

    The two-character ASCII prefixes were the actual message types for data packets, and were the input to a multi-tasking state-machine language. EM for example was (IIRC) part of email, perhaps to turn on the 'MAIL' icon. (I forget all the codes, I'm afraid).
    Z on the front seems to be an AOL addition.

    I was at PlayNet from Feb '84 to Feb '86 (when we declared bankruptcy). AOL licensed the PlayNet software from us for a song when we were running out of money, and rebranded it QuantumLink (and made minor mods, many of which we did for them).
    PlayNet ran out of money in Feb '86, though the service continued to remain up for the 1500-3000 subs for another year or two.

    PlayNet got a cut of AOL gross revenues until they finally wiggled out of it right before launching America Online (a port of the software to the PC with considerable enhancement), at which point PlayNet's bankruptcy was closed.

    The servers were Stratus fault-tolerant machines, and as of 3 years ago they were still using them.

    They didn't manage to change the 10-character limit on usernames until a few years ago. That limit was because of the 40-character width of the C64 screen, a ',' between each name, 16(?) characters for the room name plus a space, and we wanted N (12? 15?) users in a chat room. The result was that there were 10 characters available for the username.

    The algorithm in AOL for selecting usernames that resulted in JohnQ12345 was also part of the old PlayNet (server) software. Also the default initial passwords for "marketing" accounts (i.e. the free disks) of "word-word" is another thing thought up over lunch at PlayNet that still hasn't changed.

    Many things have been added & changed - but far more than I ever expected remains the same. I figured they'd dropped the ECC protocol ages ago.

    -- Randell Jesup

  5. Open Source Linux AOL client exists. by llzackll · · Score: 5, Informative
    This has all been done years ago. Check out www.pengaol.org it's in french, but there is an english version also. PengAOL is under active development. There are a few others that were under development a few years ago, but are no longer around. There is not much as far as an interface to aol areas yet cause would need to interpret FDO script language, but they will allow you to establish an internet connection with your aol account from linux.

    If you want more info from other sites, just use this google search.