No echo response.

Hi,

When I ping between two hosts, I can see an echo request (using
Ethereal), but no echo reply generated for it. Why would WinXP not
generate an echo reply in response to a request. The packet that arrives
looks good (CRC are correct), but no reply.

Thanks,
ravi

Murty, Ravi wrote:

When I ping between two hosts, I can see an echo request (using
Ethereal), but no echo reply generated for it. Why would WinXP not

Ravi,

Do you mean that an ARP request is received but no ARP response is
sent?

If so, check if the MAC addresses of the two NICs are different.
If the still-in-development NICs depend on software/firmware
for their MAC addresses, it is possible for both of them
to have the same one. In this case, the NDIS driver and/or
upper drivers in the network stack will discard incoming packets.

Regards,

  • Harshal

Well, I started with no entries in the ARP table. Host1 was sending an
ARP request, Host2 replies with it’s MAC address, but Host1 doesn’t add
the received MAC address to its ARP table.

Then I decided to test things with ICMP and setup static ARP entries on
both hosts. Now I see an ICMP request come into Host1, but the host
doesn’t seem to generate a reply.

Ravi

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Harshal Chhaya
Sent: Monday, May 16, 2005 2:13 PM
To: Windows System Software Devs Interest List
Subject: Re: [ntdev] No echo response.

Murty, Ravi wrote:

When I ping between two hosts, I can see an echo request (using
Ethereal), but no echo reply generated for it. Why would WinXP not

Ravi,

Do you mean that an ARP request is received but no ARP response is
sent?

If so, check if the MAC addresses of the two NICs are different.
If the still-in-development NICs depend on software/firmware
for their MAC addresses, it is possible for both of them
to have the same one. In this case, the NDIS driver and/or
upper drivers in the network stack will discard incoming packets.

Regards,

  • Harshal

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@intel.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

Oh, and I am looking at the incoming ICMP requests, they have different
MAC addresses for src and dest.

Ravi

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Harshal Chhaya
Sent: Monday, May 16, 2005 2:13 PM
To: Windows System Software Devs Interest List
Subject: Re: [ntdev] No echo response.

Murty, Ravi wrote:

When I ping between two hosts, I can see an echo request (using
Ethereal), but no echo reply generated for it. Why would WinXP not

Ravi,

Do you mean that an ARP request is received but no ARP response is
sent?

If so, check if the MAC addresses of the two NICs are different.
If the still-in-development NICs depend on software/firmware
for their MAC addresses, it is possible for both of them
to have the same one. In this case, the NDIS driver and/or
upper drivers in the network stack will discard incoming packets.

Regards,

  • Harshal

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: xxxxx@intel.com
To unsubscribe send a blank email to xxxxx@lists.osr.com

No echo response. Maybe this is due to some firewall?

Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
xxxxx@storagecraft.com
http://www.storagecraft.com
----- Original Message -----
From: Murty, Ravi
To: Windows System Software Devs Interest List
Sent: Tuesday, May 17, 2005 1:05 AM
Subject: [ntdev] No echo response.

Hi,

When I ping between two hosts, I can see an echo request (using Ethereal), but no echo reply generated for it. Why would WinXP not generate an echo reply in response to a request. The packet that arrives looks good (CRC are correct), but no reply.

Thanks,
ravi


Questions? First check the Kernel Driver FAQ at http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: unknown lmsubst tag argument: ‘’
To unsubscribe send a blank email to xxxxx@lists.osr.com

Thanks Jason and Maxim. One of my connections was firewalled - I was
able to ping one way and not the other. It’s working now :slight_smile:

Ravi


From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of
xxxxx@attotech.com
Sent: Monday, May 16, 2005 2:27 PM
To: Windows System Software Devs Interest List
Subject: Re: [ntdev] No echo response.

Did you enable echo requests in the firewall? I think that by default,
its off. Go to Network properties -> Advanced -> Firewall Settings ->
Advanced -> ICMP settings and see if echo requests are being blocked.
Or, just turn off the firewall.

jason

xxxxx@lists.osr.com wrote on 05/16/2005 05:05:07 PM:

Hi,
When I ping between two hosts, I can see an echo request (using
Ethereal), but no echo reply generated for it. Why would WinXP not
generate an echo reply in response to a request. The packet that
arrives looks good (CRC are correct), but no reply.

Thanks,
ravi


Questions? First check the Kernel Driver FAQ at http://www.
osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: unknown lmsubst tag
argument: ‘’
To unsubscribe send a blank email to xxxxx@lists.osr.com


Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

You are currently subscribed to ntdev as: unknown lmsubst tag argument:
‘’
To unsubscribe send a blank email to xxxxx@lists.osr.com