Extended Traceroute 343
The following describes the parameters in the preceding configuration:
Protocol is IP. Your router can support IPX, AppleTalk, DECnet, and other protocols,
depending on the IOS software running on the router.
Destination/target to ping is
Number of pings to send is 50.
Size of each ping is 1500 bytes (datagram size).
Time to wait for a ping reply is 2 seconds (timeout)
Source address in the pings will be (one of the router's interfaces).
Alternatively, you can enter interface names—Ethernet0, for example.
Value of the TOS (type of service) field is 0 (can set to test quality of service based on
IP precedence).
"Don't fragment" bit (DF bit) in the packet is zero. Answer yes to set the bit (useful
for troubleshooting and finding the smallest MTU in the path to the target).
The Validate reply data option is off. This means the router will check ping replies
against matching identifier numbers only—a number in ping (ICMP Echo, ICMP
Echo Reply) packets used to match requests with replies (see RFC 792 for more
information). Answer yes to this option to make the router check both the identifier
number and the data payload in reply packets.
The payload of the ping packets will contain FFFF (hex), which is a binary pattern of
all ones. (The text 0x in front of a number means the number is in hexadecimal format.
For example, to indicate that 1234 is hexadecimal, type 0x1234.) This can be useful
when debugging problems that are data pattern–sensitive, especially with serial lines
and CSU/DSUs. Another good pattern to use is all zeros: 0x0000.
No IP options will be specified in the IP header. This is prompted by Loose, Strict,
Record, Timestamp, Verbose[none]. For information on IP options, see RFC 791.
The ping packets will be the same size. If you want to generate pings of varying
lengths, answer Y to Sweep range of sizes.
Extended Traceroute
Like extended ping, extended traceroute is available in enable mode.
The following example shows an output of extended traceroute. A name server is
configured on the router to get hostname information in the results instead of just IP
addresses (see "Common Configuration Tasks" later in this appendix for configuring name
Protocol [ip]:
Target IP address: www.yahoo.com
Translating "www.yahoo.com"...domain server ( [OK]
344 Appendix E: A Crash Course in Cisco IOS
Source address:
Numeric display [n]:
Timeout in seconds [3]:
Probe count [3]:
Minimum Time to Live [1]:
Maximum Time to Live [30]:
Port Number [33434]:
Loose, Strict, Record, Timestamp, Verbose[none]:
Type escape sequence to abort.
Tracing the route to www1.yahoo.com (
1 16 msec 12 msec 12 msec
2 HQ-router-2.cisco.com ( 16 msec 12 msec 12 msec
3 64 msec 64 msec 64 msec
4 blackcat.cisco.com ( 64 msec 60 msec 64 msec
5 zip-gate1.cisco.com ( 68 msec 60 msec 64 msec
6 rtr-2.cisco.com ( 64 msec 60 msec 68 msec
7 Inet-router.cisco.com ( 60 msec 60 msec 64 msec
8 j521.paloalto.bbnplanet.net ( 64 msec 64 msec 68 msec
9 h405.paloalto-3gw.bbnplanet.net ( 64 msec 64 msec 68 msec
10 cb22.sanjose-622.bbnplanet.net ( 64 msec 56 msec 64 msec
11 dc09.sanjose-55.bbnplanet.net ( 64 msec 64 msec 72 msec
12 fd3-4.SanJ.globalcenter.net ( 60 msec 60 msec 68 msec
13 hs87.SanJ.globalcenter.net ( 64 msec 60 msec 72 msec
14 sonet7.SV.globalcenter.net ( 60 msec 60 msec 64 msc
15 www1.yahoo.com ( 64 msec 64 msec 72 msec
The following describes the parameters in the preceding configuration:
Numeric display enables you to toggle the output between numeric IP addresses and
The timeout is the number of seconds to wait for a reply to each traceroute probe
The probe count is the number of probe packets to send to each router hop (Time To
Live level, see RFC 791) along the path to the target.
Minimum Time to Live specifies the TTL of the first set of probes.
Maximum Time to Live specifies the largest TTL (the maximum router hops) to use.
The trace stops when the target is reached or when the maximum TTL is reached.
Port Number sets the UDP port number to use.
The last prompt is for adding IP options to the probe packets.
The preceding traceroute output shows 15 router hops to the target. The latency of the
three probes sent at each router hop is displayed in milliseconds. To abort the traceroute,
type the IOS escape sequence:
Ctrl-Shift-6, x. See "Using the Router as a Terminal
Server (Communications Server)" later in this appendix for detailed instructions on the
escape key sequence.

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