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Using the J-Web Ping Host Tool

You can use the ping host diagnostic tool to verify that a host can be reached over the network. The output is useful for diagnosing host and network connectivity problems. The Services Router sends a series of ICMP echo (ping) requests to a specified host and receives ICMP echo responses.

Alternatively, you can use the CLI ping command. (See Using the ping Command.)

To use the ping host tool:

Select Diagnose from the task bar.
Next to Advanced options, click the expand icon (see Figure 12).
Enter information into the Ping Host page, as described in Table 57.
The Remote Host field is the only required field.
Click Start.
The results of the ping operation are displayed in the main pane (see Figure 13). If no options are specified, each ping response is in the following format:

bytes bytes from ip-address: icmp_seq=number ttl=number time=time
Table 58 summarizes the output fields of the display.
To stop the ping operation before it is complete, click OK.

Figure 12: Ping Host Page

Image s020005.gif

Table 57: J-Web Ping Host Summary

Field	Function	Your Action
Remote Host	Identifies the host to ping.	Type the hostname or IP address of the host to ping.
Advanced Options
Don't Resolve Addresses	Determines whether to display hostnames of the hops along the path.	To suppress the display of the hop hostnames, select the check box. To display the hop hostnames, clear the check box.
Interval	Specifies the interval, in seconds, between the transmission of each ping request.	From the drop-down list, select the interval.
Packet Size	Specifies the size of the ping request packet.	Type the size, in bytes, of the packet. The size can be from 0 through 65468. The router adds 8 bytes of ICMP header to the size.
Source Address	Specifies the source address of the ping request packet.	Type the source IP address.
Time-to-Live	Specifies the time-to-live (TTL) hop count for the ping request packet.	From the drop-down list, select the TTL.
Bypass Routing	Determines whether ping requests are routed by means of the routing table. If the routing table is not used, ping requests are sent only to hosts on the interface specified in the Interface box. If the host is not on that interface, ping responses are not sent.	To bypass the routing table and send the ping requests to hosts on the specified interface only, select the check box. To route the ping requests using the routing table, clear the check box.
Interface	Specifies the interface on which the ping requests are sent.	From the drop-down list, select the interface on which ping requests are sent. If you select any, the ping requests are sent on all interfaces.
Count	Specifies the number of ping requests to send.	From the drop-down list, select the number of ping requests to send.
Don't Fragment	Specifies the Don't Fragment (DF) bit in the IP header of the ping request packet.	To set the DF bit, select the check box. To clear the DF bit, clear the check box.
Record Route	Sets the record route option in the IP header of the ping request packet. The path of the ping request packet is recorded within the packet and displayed in the main pane.	To record and display the path of the packet, select the check box. To suppress the recording and display of the path of the packet, clear the check box.
Type-of-Service	Specifies the type-of-service (TOS) value in the IP header of the ping request packet.	From the drop-down list, select the decimal value of the TOS field.

Figure 13: Ping Host Results Page

Image s020006.gif

Table 58: J-Web Ping Host Results Summary

Field	Description
bytes bytes from ip-address	bytes—Size of ping response packet, which is equal to the value you entered in the Packet Size box, plus 8. ip-address—IP address of destination host that sent the ping response packet.
icmp_seq=number	number—Sequence Number field of the ping response packet. You can use this value to match the ping response to the corresponding ping request.
ttl=number	number—Time-to-live hop-count value of the ping response packet.
time=time	time—Total time between the sending of the ping request packet and the receiving of the ping response packet, in milliseconds. This value is also called round-trip time.
number packets transmitted	number—Number of ping requests (probes) sent to host.
number packets received	number—Number of ping responses received from host.
percentage packet loss	percentage—Number of ping responses divided by the number of ping requests, specified as a percentage.
round-trip min/avg/max/stddev = min-time/avg-time/max-time/std-dev ms	min-time—Minimum round-trip time (see time=time field in this table). avg-time—Average round-trip time. max-time—Maximum round-trip time. std-dev—Standard deviation of the round-trip times.

If the Services Router does not receive ping responses from the destination host (the output shows a packet loss of 100 percent), one of the following might apply:

The host is not operational.
There are network connectivity problems between the Services Router and the host.
The host might be configured to ignore ICMP echo requests.
The host might be configured with a firewall filter that blocks ICMP echo requests or ICMP echo responses.
The size of the ICMP echo request packet exceeds the MTU of a host along the path.
The value you selected in the Time-to-Live box was less than the number of hops in the path to the host, in which case the host might reply with an ICMP error message.

For more information about ICMP, see RFC 792, Internet Control Message Protocol.

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