WNOS4 Configuration Guide Mike Chace (G6DHU) (May 1992) After the German original by Mike Bentrup (DB3FL) Based on WNOS4 Program Version 4a6 1. Configuration Examples In this section can be found example configuration files for WNOS. These are also provided separately in the UK WNOS4 Distribution Pack and of course, will need to be ***EDITED*** to reflect your setup. DB3FL's original was less detailed than the examples below. I have tried to reflect the UK Packet environment, especially with respect to the forwarding of mail via the BBS system and so on. 1.1. The "alias" file This file is used for two main purposes. Firstly, to allow the definition of easy to remember names for complicated mail addresses and secondly, to define a mail 'name' that expands to more than one user. In this way, one can for example, mail to user 'john' which will be expanded by the SMTP server into some long, complicated mail address. # # SMTP server ALIAS file. This is for resolving a given target # address into a single or multiple entry mail list. # Format: # mail_alias_name call_1@host_1 [call_2@host_2]......# comments # me g6dhu@g6dhu.ampr.org mike g6dhu@g6dhu.ampr.org sysop g6dhu@g6dhu.ampr.org dave g4wrw@g4wrw.ampr.org john g4otj@g4otj.ampr.org chris g4jqd@g4jqd.ampr.org paul g1plt%g1plt.ampr.org@g1wkk.ampr.org jim g1wkk@g1wkk.ampr.org hayden g8amd%g8amd.ampr.org%g8hbe%gb7bnm@g4wrw.ampr.org peter g0bsx%g0bsx.ampr.org@g8amd.ampr.org walt gw3nyy%gw3nyy.ampr.org@g4wrw.ampr.org g0lxc g0lxc@g0lxc.ampr.org tcpip tcpip !gbr.tcpip sp sp !gbr.sp # subnet-20 dave john chris g0lxc me # Any mail sent to address "mike" will be rewritten to the address "g6dhu@g6dhu.ampr.org", mail addressed to "subnet-20" will be sent to five different users as specified by the alias. Mail addressed to "hayden" will be directed to g4wrw who forwards to gb7bnm, who forwards to g8hbe who finally delivers it to g8amd@g8amd. The tcpip alias contains some special syntax only implemented in WNOS3 and 4. If mail is received for "tcpip", a copy is dumped in the local mail file (area) "tcpip" and a copy is sent to the SMTP->NNTP gateway which then posts a copy of that message into the NNTP newsgroup called "gbr.tcpip". Obviously, this syntax is only of use if NNTP is configured into your WNOS program. Note also, that the "alias" file is scanned only once. Therefore the aliases for "tcpip" and "sp" do not result in a loop! 1.2. The "areas" File This file lists the mail areas that are publicly accessible. That is, any connected user may read mail in the specified areas. Switching to a different mail area is accomplished through the mailbox "area " command. The shorter "area" command will list all public mail areas ie whatever is in this file. # # Mail Areas File. # # Format is: # # area_name Description # tcpip -> Bulletins from the BBS Network concerning TCP/IP sp -> Bulletins from the BBS Network about SP Packet Software amsat -> Bulletins from the BBS Network from AMSAT baycom -> Bulletins from the BBS Network about BayCom Packet Software # # Due to DOS filename limits, the maximum area_name length is 8 characters. Upper or lower case may be used. The "areas" file has an important role within Store and Forward too, since bulletins in each of the areas listed will be forwarded to other mailboxes as well as a copy being held for local reading. This is covered in more detail in the "NOS Mailbox Manual" by SM0RGV, also part of the UK WNOS Distribution Pack. 1.3. The "autoexec.bat" File This is the DOS startup file installed on Barry (DC0HK)'s WNOS based packet switch. The file provides for controlled restart of the machine should any errors or a crash in WNOS occur. Like most other DOS programs, WNOS returns an error status on exit, depending on the severity of the error. These error levels can be recognised by the DOS command interpreter through the ERRORLEVEL variable. WNOS returns ERRORLEVELs above 250 as follows; 251 - Timer Loop Occurred 252 - Memory Allocation Failure 254 - Stack Violation 255 - Corrupted Memory Node Trapping each of these error levels allows a message to be put into a logfile and the program restarted in a controlled manner. REM REM DOS Batch File for WNOS REM :START @ECHO OFF CLS REM REM Start ArcNet Packet Driver REM CD \DRIVERS ARCNET 0x7e 5 0x2e0 0xd000 REM REM Clean up temporary files REM CD WNOS DELETE *.TMP REM REM Set the Timezone REM SET TZ=UTC-1UTC REM REM Set Location of the Mailer called by the WNOS 'mail' command REM SET MAILER=C:\WNOS\VIEW.EXE REM REM Delete any mail lock files REM DELETE \WNOS\SPOOL\MQUEUE\*.LCK REM REM Start WNOS REM wnos -d/wnos autoexec.wn4 REM REM Trap errors and restart according to severity REM IF ERRORLEVEL 255 GOTO REBOOT GOTO END :REBOOT RESET.COM REBOOT.COM GOTO END :END REM REM Reset drivers REM CD \DRIVERS PKTSTAT 0x7e TERMIN 0x7e CD \ REM REM The End The programs "reboot.com" and "reset.com" aswell as "warmboot.com" are supplied as part of the distribution pack. RESET.COM resets the BIOS, DOS and the Disk sub-systems back to their switch-on defaults. REBOOT.COM does a cold start and WARMBOOT.COM, a warmboot (like Control- Alt-Delete). The above file should work with MSDOS and DRDOS. 1.4. The "autoexec.nos" File This is the WNOS4 startup file in use at g6dhu.ampr.org. It is designed to test many different WNOS configurations and as such has some of the configurations are commented out. The "attach" examples below should cater for most users. # #---------------------------------------------------------------------- # General Setup Details #---------------------------------------------------------------------- # # Screen is Mono so display Status Line accordingly # attribute mono # # Reboot the machine if free memory drops below 4k # mem thresh 8000 mem reboot on # # Set interrupt buffer sizes (5 buffers each of 2k) # mem ibufs 2048 mem nibuf 5 # # Set the suffix to be added to hostnames for domain searches # domain suffix ampr.org. # # Set the local hostname # hostname g6dhu.ampr.org # # Set MYCALL (used by Mailbox and NET/ROM node) # ax25 mycall g6dhu-5 # # Set the IP address of this machine # ip address 44.131.20.3 # #---------------------------------------------------------------------- # Attach Hardware Ports #---------------------------------------------------------------------- # # Attach TNC running KISS on COM2: Serial port speed is 9600bps # This is to a 2m radio and the interface is called "144". # attach asy 0x2f8 3 ax25 144 2048 236 9600 # # Attach SLIP link running 9600bps (to sys2.g6dhu) on COM1: # The interface is called "sl0". # attach asy 0x3f8 4 slip sl0 2048 236 9600 # # Attach Packet driver looking at interrupt 62 (for G8BPQ TheNode) # #attach packet 62 slip 5 236 # # Attach Packet driver looking at interrupt 61 (for G8BPQ TheNode) # #attach packet 61 144 5 236 # # Tell TNC running NORD> nntp profile organ "84 Frankland Close, Bath, Avon, BA1 4EL" nntp profile user g6dhu nntp profile fullname "Michael Chace" nntp ihave 1 # #---------------------------------------------------------------------- # Set up TNC running TheFirmware (or any other) KISS #---------------------------------------------------------------------- # # TXdelay = 36 x 10ms # param 144 1 36 # # Persistance = 50/255 (Matches local nodes) # param 144 2 50 # # Slottime = 10 x 10ms (Matches local nodes) # param 144 3 10 # # TXTail = 3 x 10ms # param 144 4 3 # # Set Half Duplex Radio Channel working (most are!) # param 144 5 0 # #---------------------------------------------------------------------- # Tell local NET/ROM nodes that we are on-air #---------------------------------------------------------------------- # netrom bcnodes 144 netrom bcnodes 144 netrom bcnodes 144 # # The END 1.5. The "convers.cfg" File This file configures the interlinking between hosts that support the convers (and xconvers) round table conferencing servers. Hosts listed in this file will be connected automatically at program startup and a convers interlink established. # convers.cfg # # Define hosts to connect with, forming an interlinked # convers cluster. # # The hostname of this convers node # g6dhu # # Hosts to connect to, in the format: # # convers_hostname connect_protocol # g0lxc telnet g4otj xtelnet g8hbe telnet # # The End The first line specifies the hostname to recognise this node by in the cluster. It should not include a ".ampr.org" extension. The following lines indicate the hostnames of nodes that will be linked to and the connection method used to reach each. The connect_protocol may be one of "ax25", "netrom", "telnet" and "xtelnet" however, WNOS4 only supports a TCP based connection ie "telnet" or "xtelnet". Both implemented connect_protocols will autoconnect to the hosts indicated and login to the remote convers server. "telnet" builds a normal (text based) connection, whereas "xtelnet" uses LZW data compression on the link. 1.6. The "domain.txt" File Used to look up IP addresses and domain names. The UK domain.txt file is part of the UK Distribution Pack. 1.7. The "forward.bbs" File This file defines the actions to be taken to forward mail using AX.25 Store and Forward to other Mailboxes. Mail may also be forwarded to TNC based PMSs and PBBSs. Here is the forward.bbs file in use at G6DHU-5. # # forward.bbs - AX.25 Store and Forward control file # # Format: # # . # Optional # # # ..... # ------------------ # Start of next forward record # # g7xyz ax25 144 g7xyz-2 g7xyz amsat ------ gb7imb ax25 144 aqusul-2 .c imbbbs gb7imb ------ gb7wrw netrom gb7wrw gb7wrw bbsnet TCPIP @ GBR.EU # # The End The first record forwards mail to G7XYZ. This is a TNC running a PacComm PMS. All that is required is to connect to his PMS over the 2m interface, and following successful exchange of mailbox IDs, forward any mail to him that is in the g7xyz mailfile and in the amsat "area". Personal mail delivered from the g7xyz mailfile will be deleted once successfully transferred. Since the "amsat" area is listed in my "areas" file (see earlier section) messages in this mailfile will not be deleted after forwarding. In this way, public mail "areas" keep copies of messages forwarded to other mailboxes. The second forwarding record, forwards to a local mailbox which is part of the UK BBS network. To connect to GB7IMB, I must first connect to my local TheNet node (GB7UX-2, alias AQUSUL), once connected, I send it the text 'c imbbbs' which instructs GB7UX-2 to make the connection for me. Once a connection is made and WNOS sees the mailbox login banner, I forward any mail in the "gb7imb" mailfile. The last forwarding record is much the same as before except that GB7WRW appears in my NET/ROM routing table. Therefore, I can connect to it using a NET/ROM Level 4 circuit, much like using the "netrom connect" command in WNOS. Mail for "gb7wrw" is forwarded, as well as anything in the "bbsnet" area. If any messages in the "bbsnet" area are addressed to "bbsnet" I readdress them to "TCPIP @ GBR.EU" before forwarding them. Not shown here is a forwarding record that uses "telnet" as the connection method. Must hosts supporting telnet are usually capable of handling mail via SMTP and as such, Store and Forward is not often used. WNOS does two other noteworthy things when forwarding mail using Store and Forward. Firstly, if the mail was delivered to your node using SMTP, WNOS will strip all SMTP message headers (eg Received:, Date: etc) from the message as it is forwarded since BBSes don't need or understand those headers. Secondly, WNOS adds a BBS style R: header line to the message. All mailboxes add their own R: headers as they forward mail, rather like the Received: headers in SMTP. WNOS's "mbox finfo" and "mbox fnic" commands allow you to add extra information to the header. For example, I set mbox finfo "Bath, Avon" mbox fnic "GB7WRW.#41.GBR.EU" in my "autoexec.nos" file. This generates an R: header like R:920322/2203z 12345@:G6DHU.GB7WRW.#41.GBR.EU [Bath, Avon] (WNOS4) Mailboxes interpret the Heirarchical Address part of the header (G6DHU.GB7WRW.#41.GBR.EU) and use it to learn a path to your mailbox. 1.8. The "ftpusers" File This file is used to control access to the internal mailbox and the FTP server. It is Internet tradition to specify permissions for the users "anonymous", "guest" and "bbs" but not any passwords. Any users unknown to your system can then login and use it, albeit with (usually) few permissions. Also, don't forget to add an entry for yourself, the sysop, and give it all permissions. Please also note, that as my WNOS "root" is the C:\TCPIP subdirectory, my public files area is therefore "/tcpip/public", it may be different for your system. The leading "/" is taken to mean "this is a path name from the root of the disk" ie short-hand for "C:\". If you do have a different starting directory you will need to edit the "public" file area path as required. # # FTPUSERS - Access control file for FTP and Mailbox users # # Format is: # # Forward slashes "/" *NOT* backslashes "\" are used to delimit # directory names. # # The 'traditional' users # anon * /tcpip/public 3 anonymous * /tcpip/public 3 bbs * /tcpip/public 3 guest * /tcpip/public 3 nocall * /tcpip/public 128 # #----------------------------------------------------- # # here follows my user list and permissions # g6dhu mike / 127 # g4wrw dave /tcpip/public 59 g0bsx peter /tcpip/public 59 g4otj john /tcpip/public 59 g4jqd chris /tcpip/public 59 g4htv * /tcpip/public 59 g8amd hayden /tcpip/public 59 g0lxc john /tcpip/public 59 g7btd sean /tcpip/public 59 g1nmw alex /tcpip/public 59 g4fro garry /tcpip/public 59 g8dkc peter /tcpip/public 59 gb7bnm dave /tcpip/public 59 g0jps chris /tcpip/public 59 gb7sdn bbs /tcpip/public 25 g8hbe bob /tcpip/public 59 # # THE END Note that although users connecting to the mailbox via AX.25 or NET/ROM will not have to login, they will still inherit the permissions specified for their callsign (username). A "*" in the password field means accept any password. The permission is set in the following way. Select from the table below, the access to facilities you wish to grant a user. For each facility, note its number. Add all the numbers together to give the final setting for in the "ftpusers" file. 1 : Read permission 2 : Write permission (if file does not exist) 4 : File Delete and overwrite permission 8 : AX.25 Connect privilege 16 : Telnet privilege 32 : NET/ROM (NConnect) privilege 64 : Sysop privilege 128 : This user is Banned from the BBS 1.9. The "host.hlp" file This file can be used to provide a short piece of announcement text when users connect to the mailbox. This overrides the default text sent by the mailbox on connecting. Keep the text to a minimum! Welcome to the G6DHU TCP/IP Mailbox and Node in Bath, Avon The Escape Character is Control-X System running version 4 test software (Mike - 1 May 1992) ***PLEASE*** remember to edit the 'host.hlp' file supplied with the UK dirstribution pack. I must have had at least a dozen messages from users asking me why their system gave the text above when someone connected to their mailbox!! 1.10. The "nos.rc" File This file is used by the FTP client to provide autologin at a remote FTP server. Manual login is no longer necessary, just type "ftp " and when connected, WNOS logs in with your username and password at the remote machine automatically. Login is complete when the "ftp>" prompt appears in the session window. # # nos.rc - FTP Autologin control file # # Format is: # g6dhu g6dhu mike sys2.g6dhu mike remote g4wrw g6dhu mike g4otj g6dhu mike g0lxc g6dhu mike # # The End. 1.11. The "popusers" File This file controls access to the POP server if you are a mail collection point for other hosts. User and password must be separated with a colon ":", and spaces are not allowed. # # popusers - POP server access control file # # Format is: username:password: # g4otj:john: g4wrw:dave: g4jqd:chris: # # The End. 1.12. The "rewrite" File This file allows mail to be redirected to a mail file other than the default ie that specified in the To: address. See the "NOS Mailbox Manual" for further details. here is the simple rewrite file used at g6dhu. sp@* sp tcpip@* tcpip *@*.eu gb7wrw *@*.gbr.eu gb7wrw *@gb7* gb7wrw The rewrite file above specifies 5 rules on which to match addresses. The first two rules cater for the receipt of BBS bulletins mailed to me by a local mailbox. For example, it therefore does not matter if TCPIP bulletins are addressed as "TCPIP @ GBR", "TCPIP @ GBR.EU" or any other "@" address, they will always be written straightaway to the "tcpip" mail area. From then on, they can be dealt with as is appropriate; forwarded to another BBS, to users, a copy to myself etc. The last three rules are used to catch BBS style addresses and redirect the message to the "gb7wrw" mailfile for forwarding to GB7WRW (see the "forward.bbs" file example above). This means for instance, that in my favourite mailer (BM, PCElm, View etc) I can address mail to say "g7zzz@gb7zzz.#99.gbr.eu" or "g7zzz@gb7zzz" (a BBS destination address). The third rule of the "rewrite" file matches this address and so the message is redirected to the "gb7wrw" mailfile. Note that only REDIRECTION takes place, the To: address remains the same. When the mailbox forwarding timer kicks, this message will be forwarded to GB7WRW mailbox as; SP G7ZZZ @ GB7ZZZ.#99.GBR.EU < G6DHU and so be forwarded through the mailbox network to G7ZZZ at the GB7ZZZ mailbox. Please note that for this to work, you must set yourself to be your own SMTP gateway (in the autoexec.nos file) eg smtp gateway g6dhu.ampr.org 1.13. Using WNOS with the G8BPQ Node Software To be written 1.14. Using WNOS with a PK232 Multi Mode Controller The following lines may be inserted at the end of the "autoexec.nos" file in order to configure a PK232 Controller for use with WNOS. You may need to change the interface name ("144" in this case) to match yours. # # Set PK232 to KISS mode # param 144 13 17 %500 param 144 13 %500 ">awlen 8" 13 param 144 13 %500 ">parity 0" 13 param 144 13 %500 ">persist 255" 13 param 144 13 %500 ">hf off" 13 param 144 13 %500 ">packet" 13 param 144 13 %500 ">hbaud 300" 13 param 144 13 %500 ">start $0" 13 param 144 13 %500 ">stop $0" 13 param 144 13 %500 ">xon $0" 13 param 144 13 %500 ">xoff $0" 13 param 144 13 %500 ">xflow off" 13 param 144 13 %500 ">conmode trans" 13 param 144 13 %500 ">hpoll off" 13 param 144 13 %500 ">kiss on" 13 param 144 13 %500 ">rawhdlc on" 13 param 144 13 %500 ">ppersist on" 13 param 144 13 %500 ">host on" 13 # # The End. Use the command "param 144 255" to switch the controller out of KISS mode before exiting WNOS if desired. 1.15. Using WNOS with a PacComm Tiny2 TNC These commands switch a Tiny2 TNC into KISS mode # # Set Tiny 2 into KISS mode # param 144 13 %500 ">kiss on" 13 param 144 13 %500 ">restart" 13 # # The End. Use the command "param 144 255" to switch the controller out of KISS mode before exiting WNOS if desired. 1.16. Using WNOS under DesqView WNOS can be used with the Desqview (DV) multitasker. The following procedure was developed by Rick, (DA2WD/KE0GB) for his system. 1. Start DV from DOS with the "dv" command 2. Activate Learn Mode with SHIFT+ALT 3. "Start Script" appears, press Return 4. Enter "!" to the question "Press key you want to redefine" 5. Type "STARTUP WNOS" and press Return. 6. From this point on, all key presses are shown by DV. If, for instance, the DV Window is to use the whole of the screen, the following commands are necessary; Call the "Open Window" menu with the normal 2-character-command used to start WNOS. Then use "Zoom" (or Alt-Z) to expand the window. 7. Press ALT+SHIFT to end Learn Mode. 8. Press Return in response to the "Finish Script" prompt. 9. Quit DV. On being asked "Save Scripts?", enter "save them" and press Return. Enter Return in response to the security question. 10. Restart DV from scratch with the DOS "dv" command. WNOS should now start automatically. If DV is to be started from a machine boot, the lines "cd \dv" and "dv" should be in the "autoexec.bat" file. WNOS can also be used in extended 43/50 line mode. The following commands should then be used; 1. Call up the command window from DV. 2. Type "CP", to change the configuration of a program. 3. Type in the 2-character-command that starts the program. 4. Press , to call up the extended options. 5. In the "Window Position" fields, the following are usually satisfactory. Max Height: 50 Starting Height: 50 Starting Row: 0 Max Width: 80 Starting Width: 80 Starting Col: 0 6. Save the new parameters and leave the Configuration Mode. 2. Glossary ARP The Address Resolution Protocol. Used to map IP addresses to their physical link-layer addresses. On AMPRNET therefore, ARP is used to map IP addresses to callsigns and vice versa. BBS Bulletin Board System (= Mailbox). CHAT Variation on the Telnet protocol using TCP. It is implemented in most NOS versions and lives on TCP port 87. It allows a direct connection to the console of another host. CONVERS Round Table Conferencing System which lives on TCP port 3600. Allows multi user round table conferencing to be distributed across more than one host. Data transfer in WNOS uses TCP and IP. CONSOLE In this manual, the console refers to the PC. Typically, its attached screen and keyboard. CR Carriage Return. The "Return" or "Enter" key. CTRL The "Control" key. DISCARD TCP Server on port 9. Incoming frames to this port are sent an acknowledgement but are thrown away. This port is used for test purposes. DOMAIN UDP Service on port 53. Allows the querying of unknown hostnames or IP addresses on a remote domain server. ECHO TCP service on port 7. The opposite of DISCARD. Any frames sent to this port are echoed back with an Ack. Used for testing purposes. ESC The "Escape" or "Esc" key. FINGER TCP service on port 79. Allows for querying information about the users of a remote system by another. FRAME Data to send between hosts is broken into frames. They may (loosely) be thought of as packets. They hold control information such as destination address etc and the raw data to be sent to the destination. FTP TCP service on ports 20 and 21. This is the File Transfer Protocol used for moving files, both text and binary between different machines. HEADER This is the term used to describe the part of a frame that contains the control information. Typically, it contains addresses, byte counts, and other important information. HOST The way of identifying a node in a network. In AMPRNET, a host usually an Amateur Radio Station. IP The Internet Protocol. IP is responsible for routing TCP or UDP frames between hosts. The logical connections being set up and disconnected by TCP. IP is a Level 3 (Network) layer protocol. LZW A data compression method (Lempel-Ziv-Welch). WNOS uses LZW to provide real time compression of messages sent by SMTP, NNTP and the Convers system. MODE DATAGRAM Indicates that TCP/IP frames are sent using AX.25's broadcast mode (UI frames). Therefore, AX.25 is used purely as a transmission method with no active part in the connection. MODE VC Indicates that TCP/IP frames are sent over an AX.25 connection. AX.25 takes an active part in the connection by providing the means for acknowledgement and retries at the link layer. VC = Virtual Circuit (a connection). MODE IPCAM A variation on the VC mode where instead of sending TCP/IP frames across AX.25 connections with a PID (Protocol Identifier) of "IP", the normal PID of "Text" is used. This allows TCP/IP to be used in AX.25 networks that may not support PIDs other than text. MTU Maximum Transmission Unit. This is the maximum length of a frame that will be sent by IP in any one instance. NET The first implementation of Amateur TCP/IP also by Phil Karn (KA9Q). NOS built upon the experience gained during the development of NET. NET/ROM A Networking Protocol proving both routing (level 3) an Transport (level 4) functions. Now beginning to be replaced by more intelligent protocols with more power and less overhead. NNTP The Network News Transfer Protocol service on TCP port 119. Allows for the distribution of news amongst hosts defined by a heirarchy of discussion groups known as newsgroups. NOS The Network Operating System. The TCP/IP implementation developed on the IBM PC by KA9Q. PID Protocol IDentifier. This is a field in the header sent by all AX.25 Information frames. Its value determines which upper-layer (or none) are being carried by the AX.25 frame (eg PID=F0 Hex is Text, CF=NET/ROM etc). POP The Post Office Protocol service on TCP port 109. Allows collection of personal mail from a remote host. RFC Request For Comments. The set of documents (there are hundreds) which define and standardize the Internet protocols. REMOTE Usually denotes the other end of a connection. In NOS it is also a server, on UDP port 1234 that allows remote control of other hosts. RTT Round Trip Time. The time taken between sending a frame and receiving its acknowledgement from the remote end. SESSION In this manual, this is a connection setup over whatever protocol, with a remote host. SLIP The Serial Line Internet Protocol. Allows to TCP/IP hosts to communicate over a normal serial connection. SMTP The Simple Mail Transfer Protocol on TCP port 25. Allows sending, receiving and routing of personal electronic mail between users of each TCP/IP host. This is in contrast to NNTP where messages (news articles) are 'broadcast' in nature ie like BBS bulletins. SRTT Smoothed Round Trip Time. The RTT averaged over the number of frames sent in a certain time. SYSOP = SYStem OPerator. Usually the owner of guardian of the host. TCP The Transmission Control Protocol. Responsible for all aspects of connection control, setup, disconnection and ensurance that data reaches the remote host and is not lost. TCP uses IP for it's host-host routing. TCP is a Level 4 (transport) protocol. TCP/IP A generic term used for any networking system that uses TCP for Transport and IP for Network functions. TELNET A TCP service on port 23. Allows login to a remote host running TCP/IP. TTYLINK A variation of the Telnet protocol that allows a direct link to the console of another TCP/IP host. UDP The User Datagram Protocol. Like TCP, this is a Level 4 (Transport) layer protocol but only provides an unreliable connection. UDP frames are sent to host ports, like TCP but the frames are not acknowledged by that host - just acted upon if received. UDP uses IP as its routing protocol. UNIX An Operating System popular on many mini and mainframe computers. TCP, IP and UDP are almost always supported by machines running Unix. Much more powerful than DOS since it is multi-user and multi-processing by design. USER A user of a TCP/IP host. WAMPES The Wuerttemberg Amateur Multi-Protocol Experimental System. A Unix based TCP/IP implementation also based on NOS. It allows remote login to a full Unix Shell, and supports SMTP, NNTP, Convers, NET/ROM, AX.25 and all other usual TCP service. XCONVERS See CONVERS. Round Table Conferencing service on TCP port 3601. Transports conference data using LZW data compression. 2.1. The ISO Reference Model Throughout this manual, you will have read terms such as "layer 1", "the Transport layer" and so on. These terms are used in everyday "network speak". Layer and level can be used interchangeably. The International Standards Organisation has defined networking technology in terms of a 7 layer or levels reference model. Each layer has a distinct task to perform in a network. It also provides services for the layer above it to use, and uses the services of the layer below it. Briefly, the layers and their functions are as follows; 2.1.1. Layer 1 (The Physical Layer) This layer is responsible for the actual transmission of data. In our world, it is made of radios, wires, modems and so on. This is the lowest layer in the hierarchy. It deals with modulation, signalling and may perform basic error correction. 2.1.2. Layer 2 (The Data Link Layer) This layer is responsible for taking a raw physical link (eg a wire or a radio channel) and turning it into a point-to-point link that appears nearly error free to the layer above it. It does this by using framing, error correction, flow control and a retry mechanism. AX.25 is a Layer 2 protocol. 2.1.3. Layer 3 (the Network Layer) This layer masks routing and switching details from the layer above it. Its job is to get a message from source to destination without regard to the underlying network structure, be it a radio channel, wire link, Ethernet etc. It knows how to reach the other end by some addressing scheme. IP is a Layer 3 protocol. 2.1.4. Layer 4 (The Transport Layer) This layer is the last of the "communication" oriented layers. Its responsibility is to get error-free data across what appears to be an end-to-end connection. It usually deals with flow (congestion) control, fragmenting of large messages into ones that fit the lower layers and so on. TCP is a transport protocol. 2.1.5. Layer 5 (The Session Layer) Deals with the maintenance of an end-to-end connection. 2.1.6. Layer 6 (The Presentation Layer) Resolves differences in the presentation of data between one end of a session and the other. For instance, converting the IBM EBCDIC character set to the ASCII character set. 2.1.7. Layer 7 (The Application Layer) This is the top of the 'protocol stack'. It consists of the programs that are run on a machine and use the services of the levels below it. SMTP for instance, as an application that provides an electronic mail service, Telnet provides a remote login service and so on.