

                    The TCP/IP Internet DOOMer's FAQ
                    by Scott Coleman (asre@uiuc.edu)
                  and Jay Cotton (jay@calc.vet.uga.edu)
                            updated 10/16/94
                        

Introduction

id Software's DOOM is truly the Killer App of the MS-DOS world.
DOOM's popularity is so immense, it has been estimated that DOOM
is installed on more PCs than OS/2 and Windows NT combined, and
DOOM's creators commute to work in Ferarris. Interest in the game
has been so great that it has been hacked, reverse-engineered,
dissected, and enhanced more than any other game in PC history.
And now, as more and more people become hooked into the Internet,
DOOM is rapidly becoming the Killer App of the Internet, as well.

     Internet DOOM play is currently at the "clever hack" stage.
DOOM, as released by iD, supports only IPX network play and
serial play between two machines. As a result, the DOOM
documentation doesn't include any information about DOOMing
across the Internet. Of course, this also means that DOOMers
can't call id for help. The result of all this is many curious
people asking the same question: How do I play DOOM over the
Internet? Enter this document. In the pages that follow, we will
attempt to answer the most frequently asked questions about
Internet DOOM, including what you need, how to set it up, and how
to find new fragbait - er, I mean, opponents.

     DOOM across the Internet is made possible by a neat little
freeware program called iDOOM. iDOOM uses the UDP protocol (part
of the TCP/IP protocol suite) to send DOOM game information
between multiple machines on the Internet. It is based on the
WATTCP TCP/IP kernel written by Eric Engelke of the University of
Waterloo. By some strange coincidence, the authors of this
document are also the creators of iDOOM, and we have used the
program to play Internet DOOM sessions with opponents from as far
away as Estonia. In writing this FAQ, we hope that sharing some
of our experience will make it easier for you to get connected in
your own Internet DOOM sessions. NOTE: Throughout this document,
we will refer specifically to games of DOOM played over the
Internet via a DIRECT CONNECTION, i.e. no modems are involved
anywhere in the link. Note that IHHD, SLIP and PPP connections
all involve modems at some point. Although other methods of
connecting two DOOM machines together across the Internet exist,
this document will focus on direct net connections using the
iDOOM network driver program.



 Getting Prepared

     Q1: I want to play DOOM over the Internet using iDOOM. What
hardware do I need?

     To successfully play DOOM across the Internet, you will need
the following hardware:

     * A machine capable of playing DOOM (D'OHH!) 

     * A network interface card (NIC). And not just any old NIC,
     mind you - your NIC must be supported by a packet driver if
     you wish to use it to play Internet DOOM. Usually this means
     that your NIC must be an ethernet card, although iDOOM has
     been successfully played over token ring. This document
     assumes that your PC is already equipped with a suitable
     NIC, although it may currently be in use for some other
     non-TCP/IP function (such as a node on a Novell network).

     * A direct connection to the Internet. If there is a modem
     somewhere in the link between your PC and your opponent's
     PC, this FAQ is not for you. Although it is possible to play
     Internet DOOM over a modem link (either by dialing up to a
     UNIX machine and using IHHD or via SLIP/PPP), such
     connection methods are beyond the scope of this document.  
           

     Q2: OK, I've got all the hardware. What software do I need? 
               
     In addition to the hardware requirements, some software is
also required to round out your the package. Before you can play,
you'll need to pick up the following:

     * DOOM 1.2 or higher (1.7 is STRONGLY recommended, since
     this version seems to have solved some problems related to
     network games). DOOM versions 1.1 and below are incapable of
     using iDOOM.

     * A packet driver written specifically for your ethernet
     card. The Packet Driver is what lets iDOOM (and therefore
     DOOM) "talk" to your NIC.

     * iDOOM.EXE, the Internet driver for DOOM.  
     
     * The WATTCP Applications. These are not absolutely
     necessary, but can definitely be useful for debugging and
     testing your setup. 

     Q3: Hold on - I don't have some of this software! Where can
I get it?

     * To obtain iDOOM: Log on to ftp.vet.uga.edu via anonymous
     ftp. Change to directory /pub/doom. Download the file
     IDOOM11.ZIP. Version 1.1 is the latest version of iDOOM as
     of this writing. 

     * Many ethernet cards come with the appropriate packet
     drivers on a utilities diskette packaged with the card. If
     your card does not come with a packet driver, there is an
     excellent collection of freely available packet drivers
     called the Crynwr (nee Clarkson) Packet Driver collection.
     You can obtain it via anonymous ftp from oak.oakland.edu.
     Change to the /pub/msdos/pktdrvr subdirectory and download
     PKTD11.ZIP and PKTD11C.ZIP. The files PKTD11A.ZIP and
     PKTD11B.ZIP contain source code and example programs for the
     packet drivers - you won't need these in order to play
     iDOOM.

     * To obtain the WATTCP applications, ftp to
     dorm.rutgers.edu, change to the /pub/msdos/wattcp/
     subdirectory, and download file APPS.ZIP.
               
     Q4: OK, I've got everything, now what do I do to set it up? 

     Setting your computer up for TCP/IP access is very
straightforward. As an illustration, I'll be taking you through
the steps necessary to set up a PC with an SMC ethernet card and
the IP address 128.192.23.5. You'll of course need to substitute
your own specific information in place of the examples given
here. All set? OK, let's get started.

     Step 0: START WITH A CLEAN BOOT!!!!! Set up your CONFIG.SYS
and AUTOEXEC.BAT files to load as few drivers as possible. This
includes such things as memory managers (HIMEM, EMM386, QEMM,
etc.) and network drivers (e.g. LSL, IPXODI). DOOM doesn't need
the former, and the latter will probably conflict with the packet
driver. We recommend that you prepare a boot floppy with a
CONFIG.SYS containing only a FILES=20 line, and an AUTOEXEC.BAT
containing only the line "prompt=$p$g".

     Step 1: Set up the packet driver. Determine your ethernet
card's IRQ setting, it's base I/O port setting, and it's memory
address setting (if any). You should be able to determine this by
looking at the card itself and consulting the user manual. You'll
need some if not all of this information, depending upon which
packet driver you use and/or type of hardware you have (for
example, some IBM computers with the MicroChannel bus can
determine the settings on the card automatically without you
having to supply them on the packet driver command line). Unzip
the appropriate driver from Crynwr Packet Driver collection
archive. In our example case, the packet driver is called
SMC_WD.COM. By looking at the jumpers on the card and consulting
the manual, I determined that the card has been set to IRQ 7,
Base I/O port address 300h, and the base memory address is at
segment d800h. For this example, I have chosen to use interrupt
60h for the packet driver. Packet drivers typically operate on an
interrupt in the range of 60h to 80h inclusive; since nothing
else in my sample system happens to be using the first available
interrupt (INT 60h), I chose that. Thus, to load my packet
driver, I use the command line


     SMC_WD 0x60 0x7 0x300 0xd800

where 0x60 is the packet driver interrupt, 0x7 is the IRQ setting
on the card, 0x300 is the I/O port base address, and 0xd800 is
the memory base address (NOTE: all numbers are in C-style HEX
notation). Don't worry if you don't understand what all this
stuff means - as long as you use the correct numbers, your packet
driver should work. NOTE: If your PC is currently part of a
Novell network (e.g. Netware, Netware Lite, Personal Netware) the
parameters you need can be found in a file called NET.CFG,
usually located in your \NOVELL, \NWLITE or \NWCLIENT
subdirectories (along with all the other drivers needed by
Novell). 

     At the very minimum, the packet driver should give a sign on
message and report the ethernet address of your NIC when you load
it. Chances are that if your NIC has been functioning properly
for other tasks (e.g. as a node on a Novell network) then you'll
have no problems here. If not, or if there are any error or
warning messages, something is wrong. One possibility is that one
of the settings on your NIC is in conflict with those of another
expansion card in your system. No two cards can have the same
IRQ, I/O port, or memory address settings, nor can the memory
areas of two cards overlap. Whatever the cause, you'll need to
find and correct the problem before continuing.

     Step 2: Set up your WATTCP.CFG file. Your WATTCP.CFG file
contains important parameters used by the WATTCP TCP/IP kernel.
These values MUST be entered correctly if you wish to make a
connection with another DOOM PC. In preparation for this, you'll
need several bits of information. Contact the network
administrator for your site and find out the IP address for your
machine, the IP address for your gateway or router, the IP
address of at least one Domain Name Server local to your site,
and your netmask value. The three IP addresses will each consist
of four groups of digits separated by periods. In our example,
the machine's IP address is 128.192.23.5, the gateway is
128.192.23.1, the netmask is 255.255.255.0, and the nameserver
address is 128.192.44.67. NOTE: it is important to use the
numeric IP addresses, not the actual host names. NOTE: If you
have other Internet programs currently installed on your machine,
such as a Gopher client or the Trumpet newsreader, you can
probably find the information you need in the configuration files
used for those programs. If the application is based on the
Waterloo TCP package, it will have it's own WATTCP.CFG, in which
case you can simply copy it over to your DOOM directory. When you
have collected all this information, unzip the iDOOM distribution
archive (e.g. IDOOM11.ZIP) into your DOOM (or DOOM2) directory.
Use your favorite ASCII text editor to edit the file called
WATTCP.CFG. Edit or add the following lines in WATTCP.CFG:

my_ip=
gateway=
nameserver=
netmask=

     On our example machine, the WATTCP.CFG file looks like this: 
     
my_ip=128.192.23.5
gateway=128.192.23.1
netmask=255.255.255.0
nameserver=128.192.44.67

     Save the changed file and exit back to DOS.


     If you know your machine's IP address, but you can't
determine the other values, you can often get away with some
educated guesswork. For instance, the gateway for a subnet
usually has an IP address ending in .1, as is the case with our
example. Thus, if your IP address is xxx.yyy.zzz.www, try setting
your gateway's IP address to xxx.yyy.zzz.1. As for the subnet
mask, a common value for this parameter is 255.255.255.0. In some
cases, the gateway value can be something like xxx.yyy.1.1 with a
corresponding netmask value of 255.255.0.0 - if one doesn't work,
it can't hurt to try the other. Finally, if you don't know your
nameserver's IP address, you can probably get by without it for
the purposes of DOOM playing. Since you'll be specifying IP
addresses for all of your opponents' machines, a nameserver
lookup won't be necessary to resolve their addresses. 

     Step 3: Test your TCP/IP setup. Load your packet driver with
the appropriate interrupt, IRQ, I/O and memory addresses. Next,
unzip the TCPINFO and PING programs from the WATTCP apps archive
into your DOOM directory. At the DOS prompt, type:

          TCPINFO    

and press the <Enter> key. If your WATTCP.CFG values are set up
correctly, and if your packet driver and net connection are
functional, you'll see a couple of screens of information about
your system, including your ethernet address and the parameters
you specified in the WATTCP.CFG file. 

     If everything looks OK, the next step is to use the PING
program to attempt to establish contact with your subnet gateway.
At the DOS prompt, type

     PING <yourgateway's.numeric.ip.address>

and press the <Enter> key. After a brief delay, you should see a
message telling you that the host is responding, as well as the
round trip time for PING's test packets. If you see the "Timeout"
error message, then something is wrong with your setup; if your
PC is unable to reach your gateway, it will be unable to reach
the rest of the Internet as well, since all network packets which
are sent to nodes outside of your local area network must pass
through your gateway. For our sample system, we would type:

          ping 128.192.23.1

If your gateway PING was successful, try PINGing your Domain Name
Server (at the IP address you specified in WATTCP.CFG) as well as
some well-known site on the internet (e.g. infant2, which is at
IP address 129.79.234.115). These will test your machine's
ability to connect with other machines outside of your subnet as
well as those outside of your site. All of these PINGs should
result in a "host responding" message with a response time. If
any of these attempts fails, recheck your entries in WATTCP.CFG
and/or get some help from your network administrator. Examples
for our test system:

     ping 128.192.44.67

and

     ping 129.79.234.115


Put Me in, Coach - I'm Ready to Play! 
     First, go find up to three of your most patient frag
buddies. Since this is your first attempt at Internet DOOM, it's
best to try and find someone on your local network who's willing
to put in a little frag time with you. Connections on your local
net will be faster and less problematic, whereas if you attempt a
long distance connection your first time out, you'll have a hard
time discerning problems caused by distance from problems caused
by an incorrect configuration.

     Decide amongst yourselves which machine will be the "server"
(the remaining machines in the game will all be "clients"). The
server machine (and there can only be ONE server per game) acts
as the coordinator for that session. The player operating the
server is in some sense "the boss" - she can decide when to start
the game, which parameters (e.g. -altdeath, -nomonsters, -warp, -
skill, etc.) will be used, whether to kick a player out, and so
on.

     The server starts iDOOM as follows:

iDOOM -server [other game parameters]

     Once the server has started iDOOM running, the clients (all
remaining players) can then connect to the server. Each client
invokes iDOOM using the command line:

iDOOM -client <server_address>

     As an example, consider several computers which are part of
a local area network in a computer lab. In this lab there are
identical machines sitting side by side, with sequential IP
addresses, i.e. 128.192.23.4, 128.192.23.5, and 128.192.23.6.
After stepping through the basic configuration process outlined
above on all test machines, my frag buddies and I are ready to
begin. First, we all agree to play our favorite DEATHMATCH level,
DOOM I episode 1 map 5. We also agree to play in -altdeath mode,
with -skill 5 and -nomonsters. On my machine, which we decided
will be the server, I type:

iDOOM -server -warp 1 5 -altdeath -skill 5 -nomonsters

     The iDOOM screen comes up, and a message is displayed
informing me that iDOOM is entering server mode. This screen is
divided into several sections: the credits, the output window,
the status bar, and the input line. At the top of the screen is
the name of the program, its version number, and the copyright
notice. The large area beginning with the second screen line and
continuing to the 22nd screen line is the output window. Here is
where iDOOM will display all status messages as well as the chat
text entered by the other players. Below the output window is the
status bar, where the current game settings are displayed. Below
the status bar is the input line where all the text I type on my
keyboard will appear. Finally, the bottom line of the screen
lists significant contributors to iDOOM.

     Once my iDOOM server is up and running, all the other
players can connect to it. The other guys type:

iDOOM -client 128.192.23.5

     Each client's screen layout is identical to that of my
server. iDOOM displays a message confirming that it is entering
client mode and connecting to the server. As each client's
connection is established, the arrival of each player is
announced by the server. 

     During this phase of the game setup, all players who have
connected thus far can type messages to each other using iDOOM's
built-in chat facility. To send a message to the other players in
the game, I simply type my message on the keyboard. My keystrokes
appear in the input line at the bottom of the screen, and when I
press <ENTER>, the text will be echoed to the screens of all
players (along with an indication of who sent the message). The
identical procedure can be used to send messages from each of the
client machines. The server itself will also send messages.
Messages from the server will begin with three asterisks ("***"). 

     When a client connects to the iDOOM server, the client
receives a message containing the game parameters which will be
used during that session. These game settings will be displayed
on the status bar. The settings are abbreviated to ensure that
they will all fit within the available space. These game settings
may be changed interactively at the server console.

     My friend sees that I have selected E1M5 as the default
episode and map for our game. He reminds me that we've been
playing that one a lot lately, and suggests we change to E2M2
since we haven't played that one in a while. I agree, and issue
the commands /episode 2 and /map 2 to change the level. Our
status lines are immediately updated to reflect these changes.

     Once I have determined (via the chat facility) that everyone
is ready to begin the game, I press the F10 key. The iDOOM server
signals the clients that the game is beginning, the chat facility
is shut down, and iDOOM sets up the connections which will be
used for the actual game. Once these network links are
established between all the machines, the message "Prepare to
meet your DOOM!" is displayed, followed by the usual DOOM startup
information. Shortly thereafter, the screen melts away and there
we are, in E1M5, pistols at the ready! 

     Give your buddies a good thrashing - you've earned it! Now,
after you've gotten DOOM working on your own subnet, you're ready
for the final step. Find a partner who is also capable of playing
Internet DOOM. Watch the posts in alt.games.doom, or tune into
the #doom, #tcpdoom or #iDOOM channels on irc. You and he will
negotiate game parameters, such as which map to play, which skill
level, and so on. You'll also decide on who will be the server
and who will be the clients (experienced DEATHMATCHers will often
try very hard to avoid being the server, since that player's
uniform is colored day-glo green and is easier to spot in a
DEATHMATCH). Now simply add the parameters you've agreed on to
the iDOOM server command line you used before. A typical          
command line will look something like

          iDOOM -server -skill 5 -nomonsters -deathmatch 


Oh Oh - It's Not Working!

          OK, so you've done everything, just like I've shown
you, but you're still having problems. The following are some
suggestions to try in case of trouble.

     Q: When I try to connect to the iDOOM server it returns to
DOS saying "Server is not responding" or "Remote reset
connection."

     A: This means that the player on the server machine hasn't
yet  started the iDOOM server. The server must be started before
the clients try to connect to it. Try again in a few seconds.


     Q: I keep seeing an "ICMP: port unreachable" message on my
screen.

     A: This message is generated by the other machine when the
port being requested by the sender is unavailable on the          
destination machine. I've seen this happen in some cases when I
started iDOOM before the other player did. Once the other iDOOM
was running, the ICMP: messages went away, and the game linked up
normally. If you see this message, you might also want to try
using a different port (see the iDOOM documentation on the -port
command line parameter). 

     Q: The music starts up fine, but all I see is a BSOD (Black
Screen of Death).
     Q: My machine displays "sending network start info" or
"listening for network start info" and then locks up. 

     A: This problem can have several causes. Perhaps the server
specified a DOOM II game, but one of the players didn't have DOOM
II. Perhaps one of the other players' machines is slower than the
others, or has a fragmented disk and takes a longer time to load
DOOM at startup. Or perhaps some packets were lost - iDOOM uses
UDP (user Datagram Protocol) packets to exchange game information
between all machines in the game. UDP packets are not guaranteed
to reach their destination, and there is no mechanism for the
sender to even be informed that what it sent never made to the
destination machine. iDOOM is designed to compensate for these
lost packets to the extent possible, and occasionally this
detection and correction takes a few extra seconds. You should
always wait for at least 30 - 45 seconds for the other DOOM
engines to sync up before you abort the setup. 


Pointers and Tips for More Fragging Enjoyment 

     We'd like to leave you with a few experiences and opinions
about Internet deathmatches.

     First, try not to use the "pause" key. Do NOT use the pause
key just so you can type a message. DO use the pause key if you
have to answer the phone; either find a hiding place to hole up,
or if you are fragged, just stay dead (don't hiot the spacebar)
until your call is completed. It's inconsiderate to make everyone
else wait on you. Do NOT release the pause after someone else
pauses.  It's hard to yell at someone over an IP connection. It's
really annoying to play against people who like to pause just
when they're about to be shot.  Argh!

     Second, DO type messages. A pause at the beginning of the
game is OK just to see if the other player is there.  If you
notice a sudden increase in game speed, another player may have
aborted or crashed. You might end up playing by yourself if you
are not alert... If you can monitor network traffic (I have a
repeater nearby that gets very busy when I play), notice the
difference between the amount of traffic when connected and
disconnected. 

     Third, Be patient. It sometimes takes 30-60 seconds for the
connection to complete. The first phase, finding a node, should
be immediate. As mentioned above, if you cannot find a node,
something is wrong. The second phase, looking/sending network
start info, may take 30 seconds, longer if one of the players has
a slow or fragmented hard disk (this is the phase where DOOM
loads the info it needs to play from the WAD file(s)).  The third
phase, sometimes a blank screen just before the game loads, may
take another 15-30 seconds.  After finding a node, please don't
abort until you have waiting a sufficient time for a connect.
Also, if your connection doesn't work the first time, try again
immediately! If it failed on your end, chances are it failed on
the other end, also, and your partner will be back in iDOOM
trying to connect and wondering where you are.

     Forth, Internet games will self abort sometimes with errors.
Don't panic, just restart iDOOM. Sometimes one of the computers
will lock up - again, just restart. If you get tired of
restarting (this doesn't happen much), just walk away! It's just
a game!

     Last, hope for a fast connection. This isn't always a
problem, but when the connection is slow, the game sucks! There's
nothing you can do about it. Sometimes the game will speed up and
slow down throughout the match.  Such is the Internet.
Re-connection will not help. Every packet that is sent back and
forth picks a new path; sometimes it's a fast path, and sometimes
not.


Finding Other iDOOM Players

     There are many ways to find opponents for your TCP/IP
Internet DOOM games. One is to contact your friends who play DOOM
and arrange a time for a game. However, everyone will
occasionally find times when nobody they know is available to
play. Fortunately, there are some virtual equivalents to walking
down to the basketball court and joining a pickup game. 


                                    IRC

     If your setup is capable of Internet DOOM, then you can
probably also use IRC, the Internet Relay Chat. If you have an
account on a UNIX machine, try typing irc at the command prompt -
chances are good that a client has already been installed which
you can access. If not, IRC clients for your PC can be obtained
via anonymous ftp from cs-ftp.bu.edu. One especially nice one (if
you run Windows) is WSIRC. To meet other players, join either the
#tcpdoom of #iDOOM channel - the sole purpose of these channels
if for Internet DOOM players to meet other players and arrange
games. The #doom channel is for more general discussions of DOOM.
Although some people also arrange games there, #tcpdoom is the
preferred meeting place. You will be able to find iDOOM games
here at almost any time of the day or night. 

     When you /join the channel, be friendly. Say "Hi" to
everyone, then ask is anyone is up for iDOOM DEATHMATCH. If you
don't get any responses right away, just hang out for a while and
watch, or engage in some random chit-chat. The people currently
on the channel might be already be playing a game (/away), and
thus cannot respond to your invitation immediately. It's quite
common for players who have two machines to use one as an irc
terminal and the other for playing DOOM. Thus, they may not be
looking at their irc screen when you first sign on. Sooner or
later, though, someone will sign on (or return) who would also
like to play. Don't make the mistake of re-posting every couple
of minutes, or bombarding everyone who joins the channel with
your request - such behavior will quickly annoy other users and
may result in your being flamed or even kicked off the channel.
Don't worry about missing any opportunities - other players who
want a game will most definitely follow the same procedure you
did - they'll ask the for a game shortly after joining the
channel. When you see the invitation, that is your cue to
respond. You can then negotiate your game parameters. Also, if
you're in a computer lab (and thus have two machines right next
to each other) you can stay logged on to irc with one machine
while you play iDOOM with the other, as mentioned above. This can
come in VERY handy in case of connection problems!


                        Frag Servers/Frag Trackers

     Frag Servers are a recent development. They facilitate iDOOM
connections between multiple players quickly and easily and with
a minimum of command line typing. Current versions of the Frag
Servers are very similar to the server built into iDOOM. NOTE: An
iDOOM client can NOT connect to a Frag Server. Frag Servers have
their own client program which then loads iDOOM as the network
driver. 

     As of this writing, the latest version of the frag
client/server package is TCPSRV12.ZIP, available from one of the
infant2 mirrors in the /pub/doom/multi_doom/net directory. A
couple of the more popular fragservers can be found at
ararat.cs.ucdavis.edu and patriot.et.buy.edu. Both of these
support 2, 3 and 4 player games on ports 1666, 1667, and 1668
respectively.

     Future versions of the Frag Servers (which will be known as
Frag Trackers) will serve as online meeting places where DOOM
players can log on, see a list of games which are awaiting
players, and either join an existing game or register a new game.
Waiting players will be able to send chat messages to each other,
negotiate and set game parameters, check connection quality, etc.
Although this exciting capability does not exist in the current
Frag Servers, it will be available sometime in the near future,
and will revolutionize the way Internet DOOM is played.


                   The TCP/IP DOOM Tournament

     You call also compete in the ongoing TCP/IP Doom Tourney.
Contact Jay Cotton at jay@calc.vet.uga.edu for information on
joining the tourney. Jay maintains a ranked listing of active
Internet DOOM players as well as an Internet DOOMer's mailing
list.

                         A Final Thought

     The TCP/IP Internet DOOM and the IRC can be VERY addictive.
Have fun, but don't lose your "real" life just to play a game!


