Trace Options with LANCOM Routers

Trace output – information for professionals

Trace output can be used to check the internal processes in the router during or after configuration. Traces can be used, for example, to display the individual stages of PPP negotiation. Experienced users can read this output and discover any errors in connection establishment.

Especially positive: The error may be located in the configuration of your own router or in the peer device.
Trace output has a slight time delay from the actual event, but the order of events is always recorded correctly. This generally does not influence the interpretation of the display, but this should be considered when making precise analyses.

How to start a trace

Trace output is started in a telnet session. Set up a telnet connection to the device. Call the trace with the following syntax:

trace [key] [parameter]

The command trace, the key, the parameter and the combination commands are each separated by a space.

Overview of keys

This key ...	... brings about the following response in combination with trace
?	displays help
+	switches trace output on
-	switches trace output off
#	toggles between the different trace outputs
no key	displays the current status of trace

Overview of parameters

The traces available for a particular model can be displayed by entering trace without any arguments.

This parameter ...	... results in the following display
Status	Connection status messages
Error	Connection error messages
IPX router	IPX routing
PPP	PPP protocol negotiation
SAP	IPX service advertising protocol
IPX watchdog	IPX watchdog spoofing
SPX watchdog	SPX watchdog spoofing
LCR	Least-cost router
Script	Script negotiation
IPX RIP	IPX routing information protocol
Firewall	Displays firewall events
RIP	IP routing information protocol
ARP	Address resolution protocol
ICMP	Internet control message protocol
IP masquerading	Events in the masquerading module
DHCP	Dynamic host configuration protocol
NetBIOS	NetBIOS administration
DNS	Domain name service protocol
Packet dump	Displays the first 64 bytes of a packet in hexadecimal
D channel dump	Traces the D channel of the ISDN bus connected
ATM cell	ATM packet level
ATM error	ATM error
ADSL	ADSL link status
SMTP client	Email processing with the integrated mail client
Mail client	Email processing with the integrated mail client
SNTP	Simple network time protocol
NTP	Timeserver trace
Connact	Messages from the activity protocol
Cron	Activities of the scheduler (cron table)
RADIUS	RADIUS trace
Serial	Information on the state of the serial interface
USB	Information on the state of the USB interface
Load balancer	Information on load balancing
VRRP	Information on the virtual router redundancy protocol
Ethernet	Information on the Ethernet interfaces
VLAN	Information on virtual networks
IGMP	Information on the internet group management protocol
WLAN	Information on activity in the wireless networks
IAPP	Trace on inter access point protocol giving information on wireless LAN roaming
DFS	Trace on dynamic frequency selection, automatic channel selection in the 5 GHz wireless LAN band
Bridge	Information on the wireless LAN bridge
EAP	Trace on EAP, the key negotiation protocol used with WPA/802.11i and 802.1x
Spgtree	Information on spanning tree protocol
LANAUTH	LAN authentication (e.g. public spot)
SIP-Packet	SIP information that is exchanged between a LANCOM VoIP router and a SIP provider or a upstream SIP telephone system
VPN status	IPSec and IKE negotiations
VPN packet	IPSec and IKE packets

Combined commands

Appended parameters are processed sequentially from left to right This allows an initially invoked parameter to be subsequently restricted.

This combination command ...	... results in the following display
All	All trace output
Display	Status and error message output
Protocol	PPP and script output
TCP-IP	IP routing-, IP RIP, ICMP and ARP output
IPX-SPX	IPX routing, RIP, SAP, IPX Wd., SPX Wd., and NetBIOS output
Time	Displays the system time before the actual trace output
Source	Displays the protocol causing the output before the actual output

Trace filters

Some traces such as the IP router trace or the VPN traces generate large amounts of output, meaning that the output can fast become rather complex. The trace filters allow you to sift out the information that is important for you from all the trace information.
A trace filter is activated by appending the “@ “ parameter to the trace command, which initiates the following filter definition. The following operators apply to filter definitions:

Operator	Description
(space)	OR operator: The filter applies when one of the operands occurs in the trace output
+	AND operator: The filter applies when the operand occurs in the trace output
-	NOT operator: The filter applies when the operand does not occur in the trace output
"	The output must exactly match the search filter

Any character strings may be entered as operands, for example the names of remote devices, protocols or ports The trace filter then processes these data according to the rule of the operators used, in a similar way to Internet search engines. You will find examples of using filters in the ’Trace examples’ section

Trace examples

This key ...	... brings about the following response in combination with trace
trace	Displays all protocols that can generate output during configuration and the state of each output. (ON or OFF)
trace + all	Switches all trace output on
trace - all	Switches all trace output off
trace + protocol display	Switches the output of all link protocols as well as status and errors messages on
trace + all - icmp	Switches all trace output on with the exception of the ICMP protocol
trace ppp	Displays the status of PPP
trace # ipx-rt display	Toggles the trace output of the IPX router and the display output.
trace + ip-router @ REMOTE-A REMOTE-B	Switches the output of the IP router on for all output involving remote devices A or B
trace + ip-router @ REMOTE-A REMOTE-B -ICMP	Switches the output of the IP router on for all output involving remote devices A or B which does not use ICMP
trace + ip-router @+ TCP + "port: 80"	Switches the output of the IP router on for all output using TCP/IP and port 80. “port: 80” is enclosed in quotation marks in order to include the space in the character string

Recording traces

We recommend the following procedure in order to record a trace simply and easily (for example, for support purposes):
Please open HyperTerminal under
Start -> Programs -> Accessories -> Communications -> HyperTerminal
Enter any name you like.

In the ’Connect to’ window, select TCP/IP from the pull-down list presented in ’Connect using’. Subsequently enter the local/public IP address, or the FQDN, of your device in ’Host address’ . Following confirmation the HyperTerminal will appear with a login prompt. Enter the configuration password.

To record the trace select Transfer -> Capture Text from the menu bar. Enter the path where you want the text file to be stored. Now switch to the dialog window and enter the relevant trace command.
To stop the trace, click on Transfer -> Capture Text -> Stop in the menu bar at the top of the HyperTerminal.

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