JNOS Commands Manual - The I Commands
The I Command Set
icmp <subcommands> These commands are used for the Internet Control Message Protocol service. icmp echo [ON | off] Display or set the flag controlling the asynchronous display of ICMP Echo Reply packets. This flag must be on for pings to work. Default is on. icmp quench [ON | off] With 'icmp quench off', when a packet is received and memory available < threshold, the packet will be dropped (i.e., no quench or anything.) The higher protocol layers will keep track of re-transmitting the dropped packets. With 'icmp quench on', when packets are received and the high water mark for dynamically allocatable storage has been exceeded, JNOS submits an ICMP Source Quench to the originator. Usually, before the originator will have reacted to the source quench, JNOS's dynamically allocatable storage will have been exhausted. What happens after that is uncertain, but it is assumed to be unfavorable. Many tcp/ip implementations don't even respond to Source Quenches at all. See also 'memory threshold command.' Default is ON. icmp status Display statistics about the Internet Control Message Protocol (ICMP), including the number of ICMP messages of each type sent or received. icmp timeexceed [<ON | off>] Allows 'time exceeded' message to be sent when the ttl of an ip packet to be routed becomes zero. When turned OFF, no message is sent which allows the system to become invisible for 'traceroutes', etc. icmp trace [ 0 | 1 | 2] Display or set the flag controlling the display of ICMP error messages. These informational messages are generated by Internet routers in response to routing, protocol or congestion problems. This only functions when in console mode. Default is 0 (off). A trace value of 1 traces all icmp packets, while a value of 2 traces only icmp types known to JNOS. ifconfig [<subcommand>] If a valid subcommand is given, it will be executed (see below). When no subcommand is given, display a list of interfaces, with a short status for each. See the 'ifconfig <iface>' command for a description of the display. ALL ax25 and MOST tcp parameters are now configurable per interface. The 'ax25 <cmd>' commands set the system default values and the 'ifconfig <iface> ax25 <command>' commands set or show the interface specific value(s). The 'tcp <cmd>' commands work in the same manner. As a result of this change, 'ifconfig' NO LONGER takes multiple commands on one line. 'ifconfig ln0 netmask ffffff00 broadcast 255.255.255.255' is invalid. The command line must be separated into two commands as: 'ifconfig ln0 netmask ffffff00' and 'ifconfig ln0 broadcast 255.255.255.255' ifconfig <iface> [<subcommands>] When only iface is given, the interface status is displayed. Interface status shows: IP addr - the ip address assigned to this interface MTU - the maximum transmission unit for this interface. Link encap - the type of link protocol to send packets with over this interface (AX.25, NETROM etc.) Paclen - if the interface is an AX.25 interface, this is the Paclen used for connections on this interface flags - interface flags, the sum of all the options set with the various commands. See below. netmask - the ip network mask. See elsewhere for a discussion. broadcast - the ip broadcast address on this interface. Used when doing arp, etc. sent ip - the number of ip packets sent on the interface sent tot- the total number of packets sent (i.e. ip, ax.25, etc.) sent idle - the elapsed time this interface hasn't transmitted any data. recv ip - the number of ip packets received on the interface recv tot- the total number of packets received (i.e. ip, ax.25, etc.) recv idle- the elapsed time this interface hasn't received any data. descr - a description of the interface Interface flag values are the sums of the following options, and can be set or unset (i.e. toggled) with the following commands (See their individual descriptions for more) command value description of flag mode iface DATAGRAM_MODE 0 /* Send datagrams in raw link frames */ CONNECT_MODE 1 /* Send datagrams in connected mode */ netrom interface IS_NR_IFACE 2 /* Activated for netrom use */ NR_VERBOSE 4 /* broadcast routes verbose */ convers interface IS_CONV_IFACE 8 /* Activated for conference call access */ ax25 bport AX25_BEACON 16 /* Broadcast AX.25 beacons */ mbox hide HIDE_PORT 64 /* Don't show port in mbox 'P' command */ ax25 digi AX25_DIGI 128 /* Allow digipeating */ arp eaves ARP_EAVESDROP 256 /* Listen to ARP replies */ arp poll ARP_KEEPALIVE 512 /* Keep arp entries alive after time-out */ ax25 hport LOG_AXHEARD 1024 /* Do ax.25 heard logging on this interface */ ip hport LOG_IPHEARD 2048 /* Do IP heard logging on this interface */ mbox noax25 NO_AX25 4096 /* No ax.25 mbox connections on this interface */ mbox bbsonly BBS_ONLY 8192 /* BBSes only on this iface */ mbox usersonly USERS_ONLY 16384 /* Users only on this iface */ mbox sysoponly SYSOP_ONLY 32768 /* Sysops only on this iface */ ifconfig <iface> ax25 [<subcommand> [arguments]] Sets the value for 'subcommand' per description in the ax25 commands. 'ifconfig <iface> ax25 ?' by itself displays the following list of accepted subcommands: bbscall bctext blimit cdigi irtt maxframe maxwait paclen pthresh retries timertype t2 t3 t4 version window ifconfig <iface> broadcast <addr> Set the ip broadcast address of interface <iface> to <addr>. ifconfig <iface> ax25 cdigi <call> Set the 'crossband digipeater only' callsign. If this call is set, digipeating works independently from the 'ax25 digipeat' setting. Connections cannot be made to the cdigi call. JNOS will search for another ax.25 interface with the same Cdigi call as that of the interface receiving the digipeated packet, and transmit the digipeated packet via that interface. Example: ifconfig 2m ax25 cdigi 2x70 ifconfig 70cm ax25 cdigi 2x70 would allow someone to use digipeater call "2x70" to automatically transfer between the two interfaces. Note in this example you would probably wish to use beacons to ID the interfaces periodically, since the transmissions don't contain your callsign. This might argue for using a valid call-ssid as the cdigi value! ifconfig <iface> description "descr" This command sets the interface description to the string specified. If no descr is supplied (i.e. ""), the current description will be cleared. The description is displayed with the mailboxP command (if the interface wasn't hidden from that display). It is also shown in the ifconfig command. ifconfig <iface> encapsulation <mode> Sets the encapsulation for interface iface to slip or ax25. This should never be needed, since it is automatically executed when interfaces are attached. ifconfig <iface> forward <iface-2> When a forward is defined, all output for interface <iface> is redirected to <iface-2>. To remove the forward, set <iface-2> to <iface>. ifconfig <iface> ipaddress <addr> Set the IP address to <addr> for this interface. Normally the ip address is assigned from the system ip address when the interface is first attached. However, it might be necessary to change it when a system acts as a ip-gateway. ifconfig <iface> linkaddress <linkaddr> Set the hardware dependent address for this interface. For AX.25 this is the callsign. If you want to allow cross band digipeating, give each port a different ax.25 call with this command. ifconfig <iface> mtu <num> Set the maximum transfer unit to <num> bytes. ifconfig <iface> netmask <address> Set the sub-net mask for this interface. The <address> takes the form of an IP address with 1's in the network and subnet parts of the address, and 0's in the host part of the address. Sample: ifconfig ec0 netmask 0xffffff00 for a class C network (24 bits). This is related to the 'broadcast' subcommand. See also the 'route' command. ifconfig <iface> ax25 paclen <num> Set the AX.25 paclen for this interface. This is useful if you want to use a value different from the default as set with the 'ax25 paclen' command; e.g., if you have a port with an HF link, you might want to set it to 128. You can also set it to greater than 256 if you have a high speed port. (This command only works for interfaces that can carry AX.25 connections, i.e., it is not for SLIP interfaces, etc.) NOTE1: The AX.25 V2 specification specifies a MAXIMUM of 256 for paclen. If you have a paclen > 256, you may run into problems when interfacing to other non-NOS systems (in particular G8BPQ- based systems.) NOTE2: The value of paclen influences NETROM behavior if the interface is activated for netrom with the 'netrom interface' command! If the paclen for this interface is smaller than any other (netrom active) paclen, the netrom mtu value will be set to this paclen - 20 ! This is to assure that you will not get fragmentation at the ax.25 level when trying to send large data packets over netrom connections. AX.25 V2.1 fragmentation is presently handled only by NOS and derived code as far as is known. Other systems, such as TheNet, BPQ, MSYS, etc., may not include proper handling of V2.1 fragmentation. What the preceding means is, if you have a VHF port with paclen 256, and an Hf port with paclen 128, and BOTH are active with netrom, the netrom mtu will be 108 ! ifconfig <iface> rxecho <iface-2> When a rxecho interface is defined, all input from interface <iface> is also copied (echoed) to <iface-2>. To remove rxecho, set <iface-2> to "off". This feature requires that RXECHO be #define'd at compile time. ifconfig <iface> tcp [<command>] Sets or displays the 'tcp' command parameters for <iface>. 'ifconfig <iface> tcp ?' by itself displays the following list: blimit irtt maxwait mss retries syndata timertype window OUTGOING tcp connections get the values for the interface on which the initial sync packet ('connect request') is routed out. INCOMING tcp connections get the values for the interface the initial request arrives on. System default TCP parameters must be set PRIOR TO attaching interfaces. After attaching interfaces, use the 'ifconfig <iface> tcp' commands to set the interface. index [<areaname>] Causes the mailindex program to be run and re-establish the indexes for the mailbox. 'index *' indexes ALL mailbox files. info The 'info' command displays information about the NOS package. ip <subcommand> These commands are used for the Internet Protocol service. ip access <permit|deny|delete> <proto> <sourceaddr[/bits]|all> <destaddr[/bits]|all> <iface> [loport | all [hiport]] Display or set ip access controls. The ip access command controls packet routing via the specified <iface> by determining which source ip addresses <sourceaddr> are routed to which destination ip addresses <destaddr>. If no ip access commands are issued for <iface>, the default behavior is to permit all sources to access all destinations. But once an IP access command is entered for <iface>, all routes via <iface> that are not specifically permitted by an ip access command, will be denied. Execution of this subcommand will add or delete an access control entry in an internal table. Incoming packets that would be routed via <iface> are compared with the table entries for <iface>, in the order that they were added, to determine if access will be granted (and routing take place). Access will be granted only if an entry matching <destaddr> and <sourceaddr> is found with "permit" set before either a match with "deny" set is found, or the end of the table is reached. The optional /bits suffix to the ipaddr specifies how many leading bits in the ipaddr are to be considered significant in the routing comparisons. If not specified, 32 bits (i.e., full significance) is assumed. All addresses can be specified by "all". Access can be made protocol dependent via the <proto> parameter. <proto> may be 'a' for any, 't' for TCP, 'u' for UDP, 'i' for ICMP, or the IP protocol number. For UDP and TCP protocols, loport and hiport specify the port or range of TCP or UDP ports for which the access control command applies. If none or all is specified, all ports are assumed. "ip access" will display the table of current access control entries. Access commands should be entered from the most specific to the least specific, since the first match (permit or deny) encountered for a given interface in the internal table is definitive. #Example: #allow a specific AMPRnet host access to the internet ip access permit any 44.76.1.199 all eth0 #but deny all others except UDP (eg, DNS) access ip access permit udp 44/8 all eth0 all #permit only AMPRnet hosts access to RF port ip access permit any 44/8 44/8 2m ip address [<addr>] Display or set the default local IP address. This command must be given before an 'attach' command if it is to be used as the default IP address for the interface. ip encap [4 | 94] Display or set the packet ID code used for transmitted IP-IP encapsulated packets. As of 1 March 1995, the default pid is 4. ip heard Display the ip-heard list. This shows the recently heard tcp/ip systems and may be set on netrom interfaces. This See also the 'ip hport' and 'ip flush' commands. ip flush Clear the ip-heard list. See 'ip heard' and 'ip hport'. ip hport [<iface> [ON | off]] Display or set the ip-heard facility. If no argument is given, show the interfaces on which ip-heard is currently active. If <iface> is given, shows the status of the ip-heard flag for the given interface. If <iface> <on|off> is given, it will set the flag on or off. Default is on. If this flag is on, ip heard frames will be logged in a table. This table can be shown with the 'ip heard' command or with the mailbox'IHeard' command. Ip-heard logging on ax.25 interfaces logs all ip stations heard on the port, even if the system wasn't directly involved in the ip activity. For non-ax.25 interfaces, only ip frames that we were actively involved in (i.e. that we routed) are logged. (this difference is due to code internals) ip hport port1 off ip hsize [n] Default: 16 Display or set the maximum size of the Ip heard table. 0 means no limit. ip rtimer [<seconds>] Default: 30 Display or set the IP reassembly time-out. ip status Display Internet Protocol (IP) statistics, such as total packet counts and error counters of various types. ip ttl [<hops>] Display or set the default time-to-live value placed in each outgoing IP datagram. This limits the number of switch hops the datagram will be allowed to take. The idea is to bound the lifetime of the packet should it become caught in a routing loop. You should make the value slightly larger than the number of hops across the network you expect to transit packets. The default is set at compilation time to 255, the official recommended value for the Internet.
(Courtesy KBNorton Computer Services)