The JANET Terminal Access Conversion Guide Service Guide Version 3, April 1995 1 INTRODUCTION 2 PURPOSE OF THE TACS 3 WHO MAY USE THIS SERVICE 4 SERVICE ISSUES 4.1 AVAILABILITY 4.2 MAILING LIST 4.3 PROBLEMS AND SUGGESTIONS 4.4 REGISTERING FOR PSPDN ACCESS 5 USING THE TACS 6 GETTING TO THE TACS 6.1 FROM TELNET 6.2 FROM JANET X.29 6.3 FROM PSPDN X.29 6.4 WHAT HAPPENS WHEN YOU GET TO THE TACS 7 NAME AND ADDRESS PRESENTATION 8 CALLING FROM THE TACS TO THE TARGET HOST 8.1 CALLING TO JANET X.29 8.2 CALLING TO TELNET 8.3 CALLING VIA PSPDN X.29 8.4 COMMON FACILITIES 8.5 LOGGING INTO TACS 8.6 BREAK OUT OF CONVERTOR, AND CLOSE CURRENT CALL 8.6.1 Telnet to X.29 (JANET or PSPDN) 8.6.2 X.29 to telnet 9 EXAMPLE SESSIONS 9.1 FROM TELNET TO JANET X.29 9.2 X.29 TO TELNET CONVERSION 9.3 TELNET TO PSPDN 9.4 LOGGING INTO THE TACS 10 FEATURES AND COMMON PROBLEMS 10.1 UP-ARROW AND DOWN-ARROW KEYS 10.2 THE DELETE KEY 10.3 SCREEN ADDRESSING PROBLEMS 1 Introduction This document is provided for network service providers at JANET connected institutions, and describes the central Terminal Access Conversion Service (TACS). As the behaviour of different services varies as seen through the convertor, this description of how to use the convertor should be seen as a base from which descriptions of how to access particular services can be prepared. JANET connected institutions are free to use part or all of this document in their own documentation. This document is available on the JANET Web server www.ja.net and will be found in the area reserved for JANET documents. The purpose of the TACS is to provide a JANET conversion service between any of a) telnet - the IP-based terminal access service b) JANET X.29 - the X.25-based terminal access service c) X.29 services using public X.25 networks (PSPDN - Packet-switched Public Data Network) This version of the TACS combines the telnet-to-JANET X.29 and JANET X.29-to-telnet conversions of the earlier TACS with access to and from the PSPDN that was previously provided by the PSS gateway. 2 Purpose of the TACS With the move towards the Internet suite of protocols, the requirement for X.29 is diminishing. However, the requirement remains for terminal access to JANET hosts which do not support telnet (principally old hosts which are unable to or unlikely to be upgraded to support IP), and to services outside JANET which can be most conveniently (or only) accessed via the packet switched public data networks (PSPDNs). Provision of telnet to X.29 (and X.29 to telnet) conversion removes a dependency on X.25 both for individual sites and for JANET as a whole, by allowing telnet access to such services. It also allows sites with only X.25 to access services only offered through telnet. The TACS now provides 'One stop conversion' between telnet and the X.25 PSPDN as well as the JANET X.29 to PSPDN service of the old PSS gateway. Since outbound calls on the PSPDN are charged for by the provider, authorisation is required to use this facility. 3 Who may use this service All JANET customers (institutions) are authorized to use the TACS for telnet-JANET X.29 and JANET X.29-telnet conversion. All JANET customers are also authorized to use the TACS for calls from the PSPDN into either the JANET X.29 service or the Internet telnet service. For calls from either telnet or JANET X.29 out over the PSPDN, no unauthenticated use is allowed. To use the TACS for this purpose, you have to obtain authentication (a userid and password) and authorisation (a call allocation) from UKERNA. See "4.4 Registering for PSPDN access" for details. The TACS may only be used to access hosts which the user is authorised to use. The TACS may not be used to deliberately conceal the original calling address. We expect that sites who authorize on calling address will want to bar calls from the convertors. The calling addresses for the TACS convertors are: JANET X.25 000040010900 IP 128.86.8.97 128.86.8.98 193.63.104.98 193.63.105.98 193.63.106.98 All the converters use the same X.25 calling address within JANET except that during the piloting of the PSPDN gatway the JANET X.25 address 00004001100 will be used as the calling address for calls originating from the pilot service. 4 Service issues 4.1 Availability The service is scheduled to be available at all times. However, if for some reason it proves necessary to take the service out of use, a warning will be issued via the tacs-users mailing list, if possible. There will be two converters deployed initially and possibly more later depending on the community requirements. 4.2 Mailing list If you wish to be included on the list, send an email to tacs-users-membership@nosc.ja.net, containing one line with the word SUBSCRIBE, and your (X.500) Directory address, e.g., SUBSCRIBE Gillman, UKERNA, UK or subscribe Robert Stone, Networks Group, ULCC, UK If you do not have a directory entry, then you may substitute your email address, prefixed by a dollar, in the subscribe line, e.g., subscribe $J.Jones@camford.ac.uk 4.3 Problems and suggestions We would appreciate feedback on problems encountered, which should be sent to liaison@mhs-relay.ac.uk. In particular, users who need to connect to hosts that require special telnet option settings or special X29 settings should send the requirements to liaison@mhs- relay.ac.uk. 4.4 Registering for PSPDN access Access via the TACS to the PSPDN requires the user to have an account on the TACS. PSPDN charges against the account are sent to the institution/user every quarter. To register, an application should be made to liaison@mhs-relay.ac.uk. The application needs to quote the name of person who will guarantee that the bills will be paid. Once the application has been authorized a username and an initial password will be sent to the user. 5 Using the TACS Since the TACS behaves in essentially the same way regardless of which conversion the user needs and how you got there, it is convenient to describe first how to get to the TACS from each environment, and then what to do when you get there. In each case, you first connect to the TACS and then enter the name or address of the host system you are trying to get to. In the text, prompts from the TACS are given in italics and what the user should type is given in bold. 6 Getting to the TACS There are several machines providing the TACS, spread across the network. The X.25 routing within JANET is arranged so that all the converters have the same address and the network sorts out which one to use. This is not feasible for IP, and so a set of four different names are registered. These each point to the most appropriate converter - if there are less than four converters, some of the names will be synonyms. The names are: lon.telnet.ja.net south.telnet.ja.net mid.telnet.ja.net north.telnet.ja.net The regions are just arbitrary areas to allow some attempt at an equitable split around the convertors, e.g. North means North Britain, not Northern England, and is mostly Scotland. 6.1 From telnet Make a telnet call to the appropriate name - the command will perhaps be: telnet north.telnet.ja.net Note: During the pilot, to make calls to the pilot TACS make a telnet call to telnet2.ja.net. 6.2 From JANET X.29 Make an X.29 call to telnet.ja.net - the same name can be used from anywhere and the network will choose the converter . The command will perhaps be: pad net.ja.telnet This example command shows the NRS name of the TACS in its NRS order, which many PADs, software and hardware, are likely to still require. Newer PADs, or reconfigured ones will be able to accept internet order for an NRS name. Note: During the pilot, to make calls to the pilot TACS make an X.29 call to telnet2.ja.net. 6.3 From PSPDN X.29 Make an X.29 call to the TACS converter. Two X.121 numbers are available, one from British Telecom and one from Mercury. The addresses to call are 23422351919190 or 23511010106190 The command may well be something like: pad 23422351919190 though there are many other possibilities depending on local provision 6.4 What happens when you get to the TACS Regardless of where you come from, you will automatically be connected to the convertor, and will get the prompt Connect to : You can then a) call some host via telnet service b) call some host via JANET X.29 c) call some host via PSPDN (if you have authorisation) d) enter one of the common facility commands (and then do something else in this list) e) login in to the TACS itself (if you have authorisation) If no response is given to the Connect to: prompt within three minutes, a timeout comes into effect, and the call is cleared. Note: If the TACS determines that you can reach the host without goiing through the TACS, you will be told so and will not be permitted to continue with the call. 7 Name and Address Presentation The name of a service (host) as entered by the user in response to the "Connect to" prompt will be one of the following: a) an Internet Domain Name, for telnet access e.g. norse.mcc.ac.uk b) an NRS name, for JANET X.29 (usually), e.g. solx.sussex.ac.uk c) a mnemonic registered on the TACS (for PSPDN, usually) e.g. lexis d) a numeric X.121 (DTE) address e.g. 228468111112 Internet Domain Names and NRS names look the same, except that NRS names used to be written the other way round, with the first element the most general (e.g. UK.AC.SUSSEX.SOLX). The Internet order, with the first element the most specific, (as solx1.sussex.ac.uk) is now recommended in the JANET community. However, older documentation and some older equipment will use the old NRS-ordering. Names to be resolved by the TACS need not be Fully Qualified. For hosts in the .ac.uk domain, the top level domain .ac.uk may be omitted. Similarly, for NRS names beginning UK.AC, the UK.AC may be omitted. Other names must be given in full, e.g. nic.ja.net. The mnemonics for PSPDN addresses are local to the TACS, and are always single element names. Within the TACS they are handled as special entries in the database that holds the NRS names. An X.121 address is between between 5 and 14 digits. If the first four digits are zero, this will be recognised as a JANET address. Anything else is assumed to be a PSPDN address - the first part identifies the country. The address should be presented with no dots or anything other than decimal digits. The name resolution algorithm for the TACS tries various steps until the lookup succeeds: i) if the "name" is purely numeric, assume it is an X.121 address - if it starts with 0000, call over JANET, if it starts 2043 then over EMPB, otherwise call over PSPDN. (Other prefixes may have special routing as well) ii) look up the name, as given, in the Internet Domain Name Service (DNS), i.e. assuming it to be a telnet host. This look up automatically tries with and without ac.uk appended iii) reverse the name, and try again in the DNS, again with and without ac.uk iv) look up the name, as given, in the combined NRS and mnemonic database. This look up automatically tries with and without UK.AC. prepended. v) reverse the name, and try again in the NRS, again with and without UK.AC. prepended. Note: The above is given for information only. Some steps above are carried out simultaneously and not necessarily in the order implied. If all of those fail, the user is prompted again, for a total of three tries. After three unsuccessful lookups, the converter disconnects. It is possible, though unlikely, for a name that is not Fully Qualified to be ambiguous when it is reversed. Using a Fully Qualified name presented in Internet order should ensure that it is tried the right way round first. 8 Calling from the TACS to the target host 8.1 Calling to JANET X.29 Call the required host, by entering Connect to: where is the name of the required host (see 7 Name and Address Presentation for details of hostnames) A number of hosts require extra information (Call User Data) or require X.25 parameters other than the PAD default for successful use. It is possible to provide this information when connecting to the host by appending the information preceded by the appropriate keyword to the hostname e.g. Connect to : uk.co.oclc.online brk=ctrl-a cud=ABCD Any number of the extra keywords can be appended to the hostname with each keyword separated from the hostname and each other by a space. Valid keywords are: brk Set the break character to a value other than brk=ctrl-a All set the break character brk=ctrl/a to control a brk=1 (ASCII character 1) rv Request reverse charging 8bit Do not strip the top bit off 8 bit characters. By default characters are 7 bit with the top (parity) bit filtered. cud Supply call user data e.g. cud=@XXXP ps Request a packet size other than the default of 128 bytes during call setup. ws Request a window size other than the default of 2 packets during call setup. e.g. ps=1024 ws=7 Try to use a packet size of 1024 bytes and a window size of 7 packets. 8.2 Calling to telnet When the prompt Connect to : appears, enter the name of the required service Connect to : where is the DNS name of the required host (see 7 Name and Address Presentation for details of hostnames) The service does not permit you to specify a port number. 8.3 Calling via PSPDN X.29 When the Connect to: prompt appears, enter the mnemonic (if there is one) or the DTE address of the target system. The TACS will then prompt for a username and password. Connect to: Username: Password: For convenience you can give either or both of these when entering the hostname using options "uid=" and "pwd=", following the mnemonic/address. TACS will prompt you for any missing info. The entered username, password pair are only valid for that one call. If you are in noquit mode, but not logged in (see below) and you make more than one chargeable call it will expect a username/password for each of the calls. When TACS prompts you for the username and password you have only one go at entering them. Get it wrong and you have to repeat the target address (fail three times and TACS will disconnect you) A list of the mnemonics currently defined on the TACS is available on www.ja.net in the area reserved for JANET documents. Suggestions for additions to the list should be sent to liaison@mhs-relay.ac.uk. 8.4 Common Facilities Various commands are available at the Connect to: prompt, instead of immediately entering the hostname: noquit retains the TACS session after end of remote host session cont synonym By default you are allowed three attempts to make a successful connection to a host. An attempt to connect to a host is considered successful if the entered hostname (or address) is valid. Connection attempts that fail because the host does not respond or because of a network failure are thus considered successful. Once the connection has succeeded and later terminated or if there are three failures you will be automatically disconnected from the convertor. Users who wish to connect to multiple hosts in one session may use the 'noquit' or 'cont' commands which they enter at the Connect to: prompt. From that point on the user must explicitly use one of the quit commands listed below to exit from the convertor. help Displays some simple help instructions news Display details of current/future events logoff Many synonyms for the exit command exit quit ex q There are also some line editing commands available when entering a hostname or commands at the Connect to: prompt you can type to delete the typed line, to reprint the typed line, to delete the last character (any character), to delete the last word typed and to exit from TACS 8.5 Logging into TACS If you have an authorisation to use TACS for chargeable (PSPDN) calls, you can login to the TACS. The command is Connect to: login You will then be prompted for the password. You can omit the username on the login command, in which case you will be prompted for it. Again, if you mistype the username/password you will have to repeat the login command. Logging in automatically sets noclear mode. Any chargeable calls will be billed against the logged-in name. The uid and pwd parameters should be omitted, and will be ignored if present. When logged in you can change your password using the password (or "passwd") command. You will be prompted for the old password and two copies of the new one. If the old and new passwords are accepted the password for that username is changed effective immediately. When logged in you can also see how much of your chargeable call quota has been used using the usage command. This displays the number of units used out of the maximum number allowed and this value as a percentage. 8.6 Break out of convertor, and close current call In the following text, indicates that the key marked 'Ctrl' or 'control' should be typed simultaneously with the key marked X. In many cases, closing down your logged-session on the host system (by exit, logoff or whatever, or rejection on failed logins), will terminate the connection from the TACS to the remote host. Unless you have set the TACS to noclear mode (by noclear or login), this will cause the TACS to disconnect you from it. However, in some cases the remote host will not clear the connection back to the TACS, and it is necessary to break back to the TACS and tell it to clear. Alternatively, you can tell your, local, terminal package to clear to the TACS. 8.6.1 Telnet to X.29 (JANET or PSPDN) When you are connected to an X.29 service through the convertor, you can force a return to the convertor by typing the break-in sequence followed by carriage return. The prompt PAD> then appears. You can use the command clear to clear the X.29 call, also ending your converter session unless you had logged in to the converter (in which case you return to the Connect to: prompt). Instead of clearing, the command "?" will display the current pad parameters. The command on your telnet package (possibly ) will get you to the command interface on your local telnet package. 8.6.2 X.29 to telnet The normal procedure is to type (i.e., Control and ]). This interrupts the convertor's telnet program, and a number of commands are then available. The command close or c closes the telnet connection, also ending your converter session unless you had logged in to the converter (in which case you return to the Connect to: prompt). An alternative is to use the interrupt key on your own host PAD. For example, with the Rainbow package, gets the PAD> prompt, and then the CLR command can be used to clear the connection to the convertor. Other PAD packages use , possibly followed by A, to enter the PAD command state. Some hosts may require special telnet protocol settings (e.g. nacsis.bl.uk which needed special echo/escape/eof etc). These requirements should be sent to liaison@mhs- relay.ac.uk. This may also apply to hosts reached via X.29. 9 Example sessions 9.1 From Telnet to JANET X.29 The first attempt shows what happens if the destination could be reached directly by the means used to reach the TACS - in this case, phoebe.ulcc.ac.uk is accessible via telnet and TACS will not do unnecessary relaying. The second attempt has an invalid name. The third attempt connects. The call would also have worked if the name had been in the opposite order. The user then breaks back to the TACS with followed by a carriage return, displays the PAD parameters and clears the call. pluto: telnet2.ja.net Trying 128.86.8.98... Connected to telnet2.ja.net. Escape character is '^]'. JANET X.29 to Telnet Convertor and gateway to X.25 PSPDN Please note that the gateway is available to authorised users only. All sites connected to JANET are authorized. If you are not an authorised site, you must disconnect immediately. At the prompt, type the name of the JANET host you wish to connect to, or `help' for help, `news' for the latest network status, or `quit' to leave the gateway. Please report any problems to liaison@mhs- relay.ac.uk. Connect to : phoebe.ulcc.ac.uk That destination may be reached without using this service Connect to : rhubarb.ac.uk No address information for rhubarb.ac.uk Connect to : uk.co.oclc.online Calling uk.co.oclc.online... Type ^P for Executive, ^Pb for break Calling... connected... YOUR TERMINAL INFORMATION NUMBERS ARE: #D007 P 2131 OCLC IS ON LINE Please log on PAD> ? [1] escape 1 [2] echo 1 [3] forward 126 [4] timeout 0 [5] padflowcontrol 1 [6] service 1 [7] breakaction 21 [8] datadelivery 0 [9] crpad 0 [10] linefold 0 [11] baudrate 3 [12] terminalflowcontrol 1 [13] linefeedinsert 4 [14] lfpad 7 [15] editcontrol 0 [16] chardelete 127 [17] bufferdelete 21 [18] displayline 18 PAD> clear Connection closed. Connection closed by foreign host. 9.2 X.29 to telnet conversion This shows a successful attempt. Note that this time TACS is quite happy to allow access to phoebe.ulcc.ac.uk when the incoming call was not via telnet. (c.f. second attempt above) PAD> call net.ja.telnet Calling... connected... JANET X.29 to Telnet Convertor and gateway to X.25 PSPDN Please note that the gateway is available to authorised users only. All sites connected to JANET are authorized. If you are not an authorised site, you must disconnect immediately. At the prompt, type the name of the JANET host you wish to connect to, or `help' for help, `news' for the latest network status, or `quit' to leave the gateway. Please report any problems to liaison@mhs- relay.ac.uk. Connect to : phoebe.ulcc.ac.uk Calling phoebe.ulcc.ac.uk... Trying 192.12.72.28... Connected to phoebe.ulcc.ac.uk. Escape character is '^]'. HP-UX phoebe B.08.00 A 9000/40T (ttyu0) login: cziwprf Password: Welcome to HP-UX on the HP 9000 Series. $ exit logout Connection closed by foreign host. Connection closed. 9.3 Telnet to PSPDN This example would have appeared exactly the same, apart from the first line, if access to the TACS had been via JANET X.29 The first attempt uses an invalid TACS username/password. The second uses a spurious mnemonic (this would have succeeded had there been a system nekhif.ac.uk). The third example has the TACS username and password presented as parameters in the calling line. pluto:telnet telnet2.ja.net Trying 128.86.8.98... Connected to telnet2.ja.net. Escape character is '^]'. JANET X.29 to Telnet Convertor and gateway to X.25 PSPDN Please note that the gateway is available to authorised users only. All sites connected to JANET are authorized. If you are not an authorised site, you must disconnect immediately. At the prompt, type the name of the JANET host you wish to connect to, or `help' for help, `news' for the latest network status, or `quit' to leave the gateway. Please report any problems to liaison@mhs-relay.ac.uk. Connect to : lexis Username: johnm Password: wrong You require a valid user ID/password to make a chargeable call Connect to : nekhif No address information for nekhif Connect to : 228468111112 uid=peterf pwd=hidden Calling 228468111112... Type ^P for Executive, ^Pb for break Calling... connected... DEC OSF/1 Version V2.0 (ties.itu.ch) ttypb login: testing ITU TIES Service ... ... 9.4 Logging into the TACS This session shows a user with an account logging on to the TACS, checking their usage and changing the password. They then make two calls, one to a chargeable PSPDN call - note the TACS username and password are not needed) - and one to an JANET X.29 site. Both sessions are cleared by breaking back to the TACS. Logging in sets noclear mode, and the TACS session is concluded with the logoff command. pluto:telnet telnet2.ja.net Trying 128.86.8.98... Connected to telnet2.ja.net. Escape character is '^]'. JANET X.29 to Telnet Convertor and gateway to X.25 PSPDN Please note that the gateway is available to authorised users only. All sites connected to JANET are authorized. If you are not an authorised site, you must disconnect immediately. At the prompt, type the name of the JANET host you wish to connect to, or `help' for help, `news' for the latest network status, or `quit' to leave the gateway. Please report any problems to liaison@mhs-relay.ac.uk. Connect to : login Username: peterf Password: hidden Connect to : usage User peterf: Has used 0 segments (no limit) on UK GNS calls Has used 0 segments (no limit) on Int GNS calls Connect to : password Changing NIS password for peterf on telnet2.ja.net. Old password: hidden New password: secret Retype new password: secret NIS entry changed on telnet2.ja.net Connect to : 228468111112 Calling 228468111112... Type ^P for Executive, ^Pb for break Calling... connected... DEC OSF/1 Version V2.0 (ties.itu.ch) ttypb login: test ITU TIES Server PAD> clear Connection closed. Connect to : uk.co.oclc.online Calling uk.co.oclc.online... Type ^P for Executive, ^Pb for break Calling... connected... YOUR TERMINAL INFORMATION NUMBERS ARE: #D041 P 2040 OCLC IS ON LINE Please log on demo PAD> clear Connection closed. Connect to : logoff Connection closed by foreign host. 10 Features and common problems You should be aware of the following areas where problems may arise: 10.1 Up-arrow and down-arrow keys Certain terminal emulators (for example, the Windows Terminal utility version 3.0 used on IBM PCs) use these keys to scroll up and down screens. (Version 3.1 and later pass the up-arrow and down-arrow keys.) They will not then be passed to the application, which may be a screen editor requiring them to move around the screen. It may be necessary for support staff to experiment with, and then advise their users, on the use of alternative emulators. 10.2 The delete key The delete key is occasionally different when a service is accessed through the convertor to what it is when the same service is accessed directly. If it is the first time you access the service, it is sensible to experiment as follows. Try firstly the character you expect it to be, then try del, the PC's delete key, backspace, and H. For Unix end systems, the stty command may enable you to set the key you want to perform a delete action. 10.3 Screen addressing problems Screen addressing problems are sometimes experienced. The first time you use a particular host through the convertor, check for screen addressing problems; perhaps try a screen edit. If there is a problem, the solution is likely to be host (or operating system) specific. For example, with VMS, use $SHOW TERM to check that the operating system has got terminal type correct, and, if not, use $SET TERM to correct it. For Unix "csh", use setenv TERM For Unix "sh", use set TERM= export TERM And, having set your terminal type, you may wish to use the tset command to suitably initialise the terminal itself. As with the stty command it is a command best left to Unix experts. Feedback on problems encountered should be sent to liaison@mhs-relay.ac.uk.