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masks, gateway and DNS addresses and other parameters to the 
network stations. It is easy to reconfigure a network that uses a DHCP 
server - it is enough to change server settings and every station will 
automatically retrieve new configuration.

The BOOTP protocol is an earlier and simpler version of DHCP. Its 

common use is booting of diskless workstations. A workstation uses 
BOOTP to get its IP address and other network parameters together with 
TFTP server address, from which the operating system may be 
downloaded.

The DHCP protocol may deliver more working parameters 

including domain name, DNS address, print server, syslog server, X-
Window fontserver, MTU and TTL settings, and many others.

DHCP/BOOTP Relay Agent transfers DHCP and BOOTP requests 

and replies between separate networks. The DHCP and BOOTP protocols 
work only within one physical subnet. The station using such protocols 
doesn’t know its IP address yet, so its packets cannot be routed to other 
networks. Relay Agent listens for such requests and forwards them to a 
DHCP server, which may be placed anywhere in the network.

4.3.7.1. Review of the settings

Entering “dhcp” alone displays current server settings. Here is an 

example:

Tahoe> dhcp
DHCP/BOOTP server
default-lease-time 43200
max-lease-time 86400
network "lan" (eth0):
    default-lease-time 43200
    max-lease-time 86400        
    domain-name tahoe.pl
    subnet "local": 10.0.0.0/255.255.255.0
        default-lease-time 43200
        max-lease-time 86400
        filename vmlinuz.2.2.19
        next-server 192.168.0.5
    routers 10.0.0.1
        domain-name-servers 192.168.0.4
        domain-name tahoe.pl
        address ranges: 10.0.0.3-10.0.0.15
relay server 192.168.0.5 67

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4.3.7.2. Basic DHCP server configuration rules

Before starting using DHCP server please read following 

guidelines:

¡

the configuration is organized in a hierarchical manner - the most 
general group of settings is “network” - the physical network 
connected to the modem. Any number of IP “subnets” may exist 
within a network. Inside an IP subnet an IP address “range” may 
be selected - these addresses will be dynamically assigned to the 
network stations.

 A static connection between an IP address and a 

hardware address may also be set. Each group (“network”, 
“subnet”) has its own options. Creating a new group (e.g. a 
“subnet” within a “network”) causes copying of the options from 
the parent group (e.g. if the “lan” network has a “domain-name” 
option, after adding a “local” subnet within “lan” the option will be 
automatically copied - it may be modified or deleted later)

¡

on the beginning a “network” for each interface should be created 

¡

in each of the “networks” an IP “subnet” should be created 
according to IP subnets connected to that interface (modem may 
not have the routing set up to each of them - it’s enough that they 
are in the same physical network)

¡

now IP ranges and static IP entries may be added

4.3.7.3. dhcp [ on | off | relay ]

DHCP/BOOTP server may work in one of three modes:

¡

on

 - the server in enabled and answers to the requests

¡

off -

 the server is disabled

¡

relay -

 the server is disabled, but the relay agent is enabled and 

listens for the requests to be forwarded to other DHCP server

4.3.7.4. dhcp add

The “dhcp add” commands add a network, subnet, IP range, etc. 

Following variants are supported:

¡

dhcp add network <name>

Adds a new physical network connected to the modem’s interface. 

There should be the same number of “networks” and interfaces. The 
“network”-interface connection will be determined later while adding the 
IP subnets.

4.3.7.1

4.3.7.4

4.3.7.3

4.3.7.2

Summary of Contents for 684

Page 1: ...FREEDOM OF COMMUNICATION USER MANUAL G shdsl modem with built in router TAHOE 684 ...

Page 2: ......

Page 3: ...n 1 2 Interfaces 2 3 Modem configuration using built in keyboard and LCD 4 4 Configuration using telnet or serial console 9 4 1 Telnet connection 9 4 2 Serial console 9 4 3 Commands 10 5 Technical data 29 6 Declaration of Conformity 30 ...

Page 4: ...served Other trademarks of other companies are used only for explanation and to the owner s benefit without intent to infringe Tahoe assumes no responsibility for any errors or omissions that may appear in this document Tahoe makes no commitment to update the information contained here and may make changes at any time without notice ...

Page 5: ... through WWW Modem status messages can be sent to a central server using syslog protocol One network interface may support more than one IP subnetwork thanks to interface aliases eth0 0 eth0 1 etc and VLAN interfaces eth0 1 eth0 2 etc Modem may also work as a bridge in this mode both interconnected networks create one whole on the hardware level e g computers with Microsoft Windows operating syste...

Page 6: ...nnect it to a PC Three lines bolded are sufficient Terminal settings are 9600 bps 8 data bits 1 stop bit no parity no handshaking 2 2 2 Pin Name 1 DCD 2 3 4 5 6 RXD TXD DTR GND DSR Description carrier detect transmission readiness signaling data received from the PC data sent by the modem to the PC active when the PC is switched on signal ground active when the modem is switched on 7 RTS used by t...

Page 7: ...ppropriate telnet commands Modem should be connected to a Ethernet switch or a hub using a straight patch cord or to a PC a router or an uplink port in a switch using a crossed over one After connecting a LED named LAN Link should be lit In the Tahoe 684 modem the FastEthernet interface has following status LEDs LAN Link lit when modem is connected to a LAN LAN Act LAN activity blinks when data is...

Page 8: ... transmitting data D DEAC signal lost connection will be terminated W WAIT waiting before another synchronization attempt On the right of the display there is a keyboard with up down Escape and Enter keys By pressing up down buttons you may browse the configuration menu speed setting modem type setting Master Slave line modulation selection storing settings in the EEPROM memory setting the IP addr...

Page 9: ...OTE Always one modem has to be set as a Master and the other one as a Slave 3 3 Line coding After pressing Enter the G shdsl line coding signal modulation may be chosen The number 32 in the example above means the number of values encoded in one symbol 32 5 bits per symbol The higher this number is the lower is the signal frequency which gives better immunity for signal attenuation and higher reac...

Page 10: ...network mask to 255 0 0 0 After connecting to this address using telnet further configuration can be done The IP address may be changed however using the keyboard It s useful when the IP address has been changed and then forgotten After pressing Enter up and down buttons may be used to change the first octet of the IP address Then after pressing Enter second third and fourth octet may be set After...

Page 11: ... will be lost 3 9 Bridge mode This option enables or disables the bridge mode in which two interconnected LANs create one whole in the hardware layer Three settings are available off regular TCP IP routing on bridge enabled but the modem is still available under its IP address and thus may be managed remotely transparent completely transparent bridge 3 10 Line parameters The Esc button returns to ...

Page 12: ... without causing any problems with the synchronization When the NMR is less than 0 dB modems will be unable to bring the link up It is the best practice to keep the NMR equal to or higher than 5 dB so the error rate will be unnoticeable Otherwise the packets will be lost due to bit errors and the retransmission would be necessary thus decreasing the overall effective throughput This parameter is a...

Page 13: ...l appear User Access Verification Password The default password is Tahoe case sensitive If the password entered is correct a command prompt will appear Tahoe 4 2 Serial console If the telnet connection is not possible e g there s no telnet client available or the modem s IP address is unknown the modem may be connected to the PC s serial port using a null modem cable After starting a terminal soft...

Page 14: ...may be disabled using the ifconfig command If it is disabled only those stations may connect to the modem whose IP and MAC addresses are entered into the ARP table using the arp add command This way an unauthorized network access may be prohibited 4 3 3 bridge The bridge command enables or disables the bridge mode in which two interconnected LANs create one whole in the hardware layer The stations...

Page 15: ...rebooting the modem it will return to its factory defaults Until the reboot it will continue to run with its current settings which can be saved again using write command 4 3 5 config The config command displays current configuration The command output may be entered on another modem to make an exact copy of the configuration 4 3 6 console This command is used to enable or disable password the pro...

Page 16: ...gent transfers DHCP and BOOTP requests and replies between separate networks The DHCP and BOOTP protocols work only within one physical subnet The station using such protocols doesn t know its IP address yet so its packets cannot be routed to other networks Relay Agent listens for such requests and forwards them to a DHCP server which may be placed anywhere in the network 4 3 7 1 Review of the set...

Page 17: ...ay be modified or deleted later on the beginning a network for each interface should be created in each of the networks an IP subnet should be created according to IP subnets connected to that interface modem may not have the routing set up to each of them it s enough that they are in the same physical network now IP ranges and static IP entries may be added 4 3 7 3 dhcp on off relay DHCP BOOTP se...

Page 18: ...igured subnets Only this IP address will be assigned to the given MAC address dhcp add host server 00 50 13 2e 15 ca 10 0 0 5 dhcp add range start address end address Adds an IP address range from which addresses will be assigned to the network stations The address range must be contained inside one of the subnets dhcp add range 10 0 0 5 10 0 0 37 dhcp add option option value Adds a global DHCP op...

Page 19: ...tes a DHCP server address used in the Relay Agent mode dhcp del range start address end address Deletes an IP address range assigned to the network stations dhcp del option name value Deletes a global option Besides the option name its value should also be given because some options may have more than one value e g domain name servers routers etc 4 3 7 6 dhcp rename The command changes the name of...

Page 20: ...ation is switched off without releasing that address dhcp network max lease time value A station may request other lease time the negotiated time may not be higher than this setting 4 3 7 8 dhcp default lease time value dhcp max lease time value These commands are similar to those described in the previous paragraph but their meaning is global 4 3 8 dsl This is a group of commands used to configur...

Page 21: ...e TCPAM16 from 64 kbps to 2304 kbps The auto setting forces use of TCPAM32 for speeds higher than or equal to 256 kbps per line and TCPAM16 for lower rates dsl reset resets the DSL connection the synchronization is performed from the beginning Entering dsl alone displays current settings 4 3 9 exit quit The command closes the configuration session and disconects from the modem 4 3 10 fr A group of...

Page 22: ...interface may support several IP subnets eth0 1 eth0 2 etc VLAN networks LAN networks separated from each other although using the same cabling eth0 1 0 eth0 1 1 etc VLAN interface aliases fr1 fr2 etc Frame Relay PVCs the number after fr is the DLCI of a given PVC ppp0 PPP interface used when the DSL link works in the PPP mode wan0 HDLC interface used when the DSL link works in the Cisco HDLC mode...

Page 23: ...el removes an entry ipchains list displays current settings ipchains flush removes all entries from the list After the add insert or del option following parameters should be given s source subnet netmask port range Defines the source addresses which this entry concerns If this parameter is omitted then the entry concerns all source addresses d destination subnet netmask port range Defines the des...

Page 24: ...nhibit the access for the whole 215 16 11 0 24 subnet except the 215 16 11 5 address More examples ipchains add d 0 0 0 0 0 80 80 p tcp deny Inhibits access to the port 80 on all external servers ipchains add s 192 168 0 0 16 masq Enables masquerade for the 192 168 0 0 16 subnet other addresses are passed unchanged 4 3 14 keypad Allows locking of front panel keyboard Three settings are possible No...

Page 25: ...with modem type throughput and line state would be available after pressing Enter or as the last one after the screen with line parameters that is after pressing Enter three times The special characters may be used in the text displayed They will be replaced by appropriate values t modem type e g Tahoe 684 s total line throughput 1 2 3 4 state of subsequent lines e g SYNC a b c d shortened line st...

Page 26: ...bps link speed duplex half full forces half or full duplex mode power on off enables and disables the Ethernet port Choosing speed or duplex options disables autonegotiation mode 4 3 20 netstat Shows a list of active TCP connections 4 3 21 ping Checks the availability of a device with selected IP address For example ping 10 0 0 2 gives the time necessary to send packet to the 10 0 0 2 station and ...

Page 27: ...p4 options allow execution of up to four commands after the PPP link is established ppp port down1 command ppp port down2 command ppp port down3 command ppp port down4 command the down1 to down4 options allow execution of up to four commands after the PPP link is broken down ppp ppp user username sets the username used during the PPP authorization if required by the remote router ppp port password...

Page 28: ...mask network mask gw gateway adds the route to a subnet with given address and network mask through a specified gateway route add default gw address adds the default route through a given gateway route del address removes route to an IP address given route del net address netmask network mask removes route to a subnet specified route del default removes default route 4 3 27 snmp The snmp command i...

Page 29: ... ARP table it will send an answer with the correct MAC address Such request is sent by the PCs working under the Microsoft Windows operating system during the boot up If the ARP reply from the modem comes the PC will show a message that this address is occupied which will make an illegal use of that IP address impossible The strictarp mode may be disabled using strictarp off 4 3 29 syslog The mode...

Page 30: ...uring logging in The first parameter is used after the logging in and the second one optional during the log in Entering 0 disables the timer These settings are also applied to the serial console if its access is password protected using the console passwd on command 4 3 33 uptime w Shows the time elapsed since the modem booting and the current processor temperature 4 3 34 user The user command is...

Page 31: ...al b parameter may be added before MAC address to send the wake up packet as a broadcast 4 3 37 watchdog The watchdog command gives additional control over the modem s unpredicted behavior i e a misconfiguration disabling further communication with the modem The modem uses the ping command to check the availability of certain IP addresses and reboots if one of them doesn t answer The command has f...

Page 32: ...is rebooted 4 3 38 write Saves the current configuration to the EEPROM and displays an information about the EEPROM usage If the configuration is to large to be stored some settings should be deleted like static ARP entries DHCP options etc 4 3 38 ...

Page 33: ...1 2 G shdsl ITU G 994 1 G hs modulations TCPAM 32 TCPAM 16 TCPAM 8 TCPAM 4 PAM 16 PAM 8 PAM 4 PAM 2 throughput 256 19456 kbps Ethernet interface 10 100Base T RJ 45 connector serial console RS 232 DB9 M connector dimensions 200 mm width x 45 mm height x 130 mm length power supply 15 V 700 mA 11W external 100 240V 50 60Hz power supply included environmental conditions storage temperature 20 C to 70 ...

Page 34: ...rectives is ensured by complete application of the following harmonized European Standards EN 60950 2000 EN 55022 1998 EN 61000 6 1 2002 EN 61000 6 3 2002 Signed Piotr Kaczmarzyk Position Director Signature Date 10 Jan 2004 Place Wroclaw Poland 2005 Tahoe All rights reserved Other trademarks of other companies are used only for explanation and to the owner s benefit without intent to infringe Taho...

Page 35: ......

Page 36: ... TAHOE Uniwersytecka 1 50951 Wroc aw Poland phone 48 50 100 7362 fax 48 71 344 2642 http www tahoe group com ...

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