Ping Question

I see two possible sources, your ping is probably blocked by a router ACL (or a firewall) OR a device (router or firewall) doesn't know how to reach the destination network.

The message stating that 4 packets have been sent and 4 have been received is correct because the PC has sent 4 ICMP echo request and the device which block them or which don't know how to route them sent back ICMP destination unreachable packets... So the PC has well received 4 packets back but they weren't ICMP echo reply.

Regards,
Krik

I see two possible sources, your ping is probably blocked by a router ACL (or a firewall) OR a device (router or firewall) doesn't know how to reach the destination network.
Regards,
Krik

Are you sure of the what I have bolded and underlined? The error message is 'destination host unreachable'. To me it implies, the packets are being delivered to the destination network, but not to the host.

Something to think about.

Cheers

No screen shots sorry.I work in a help desk role so i dont actually see the screen myself but it has happened a few times.

I'm confused here, I assume that some one told you about the output but you did not see it your self. Can you try to let them drop you a copy of the output. It would really help.

Ammar

I see two possible sources, your ping is probably blocked by a router ACL (or a firewall) OR a device (router or firewall) doesn't know how to reach the destination network.
Regards,
Krik

Are you sure of the what I have bolded and underlined? The error message is 'destination host unreachable'. To me it implies, the packets are being delivered to the destination network, but not to the host.

Something to think about.

Cheers

It appears that Cisco router (and probably some other devices) send an ICMP destination host unreachable when destination network is unreachable... I just did a very simple test in a lab as follow :

R1 --- R2 --- R3

R1 try to ping R3 loopback, it has a route towards R2 to reach it. However R2 hasn't the route to R3's loopback. On R1 here is what a 'debug ip icmp' shows :

[code:1]R1#ping 3.3.3.3

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 3.3.3.3, timeout is 2 seconds:
U
*Mar 1 00:05:43.963: ICMP: dst (1.1.1.1) host unreachable rcv from 1.1.1.2.U
*Mar 1 00:05:46.047: ICMP: dst (1.1.1.1) host unreachable rcv from 1.1.1.2.U
Success rate is 0 percent (0/5)
R1#
*Mar 1 00:05:48.127: ICMP: dst (1.1.1.1) host unreachable rcv from 1.1.1.2[/code:1]

R2 doesn't have a route to network 3.3.3.0/24 but it sends a host unreachable to R1 instead of network unreachable...

Regards,
Krik

Kirk,

That would make sense from the router point of view however i think everyone here (well definatley me) had presumed the reply had come from the host that was being pinged.

GTM can you confirm, do the reply actually come from the end host that was being pinged or a router/firewall along the way ?

Cheers

To be honest Smurf i dont really know like i said it has happened a few times so i cant be sure if it was the exact same replys everytime because the first one or two times i didnt really think much of it.Now having said that on the last occasion this happened a tracert did not get passed the adsl router so i presume the ping replys are coming from it.