Hello,

We have three server 1.) windows 2012 2.) RHEL 6.4 server 3.) RHEL 6.4 server . and few client which have windows 0.1 pro installed.

when im trying to ping from windows 8.1 pro or windows server 2012 to RHEL 6.4 there are packet loss occurs, But when im trying to ping from RHEL 6.4 to another RHEL 6.4 im getting proper reply.

below mention reply from RHEL support there is no issue with RHEL.

Hello,

Below is the detail analysis of the tcpdumps which we have collected. I have shown two conditions when ping works properly and the other condition when it fails.

Below is the dump of normal situation when ping works properly:

tcpdump_windows:
---------------- 
No.   Time             Frame Source                Destination        Protocol   Len    Seq-Number      TTL        Info
1     0.000000000          1 10.108.3.41           10.108.1.105          ICMP     74    62885 (0xf5a5)  128        Echo (ping) request
2     0.000265000          2 10.108.1.105          10.108.3.41           ICMP     74    62885 (0xf5a5)  63         Echo (ping) reply
3     1.002776000          3 10.108.3.41           10.108.1.105          ICMP     74    62886 (0xf5a6)  128        Echo (ping) request
4     0.000319000          4 10.108.1.105          10.108.3.41           ICMP     74    62886 (0xf5a6)  63         Echo (ping) reply
5     1.003356000          5 10.108.3.41           10.108.1.105          ICMP     74    62887 (0xf5a7)  128        Echo (ping) request
6     0.000333000          6 10.108.1.105          10.108.3.41           ICMP     74    62887 (0xf5a7)  63         Echo (ping) reply


linux.pcap
----------
No.   Time             Frame Source                Destination        Protocol   Len    Seq-Number      TTL        Info
3     10.319659           3  10.108.3.41           10.108.1.105          ICMP     74    62885 (0xf5a5)  127        Echo (ping) request
4     0.000048            4  10.108.1.105          10.108.3.41           ICMP     74    62885 (0xf5a5)  64         Echo (ping) reply
5     1.003017            5  10.108.3.41           10.108.1.105          ICMP     74    62886 (0xf5a6)  127        Echo (ping) request
6     0.000034            6  10.108.1.105          10.108.3.41           ICMP     74    62886 (0xf5a6)  64         Echo (ping) reply
7     1.003622            7  10.108.3.41           10.108.1.105          ICMP     74    62887 (0xf5a7)  127        Echo (ping) request
8     0.000043            8  10.108.1.105          10.108.3.41           ICMP     74    62887 (0xf5a7)  64         Echo (ping) reply

- We can trace each packet which got send from source (Windows) and reached destination (RHEL) by its sequence number ('Seq-Number'  column) . Can see the first packet with sequence number as 62885 started from windows[Echo (ping) request], that packet with sequence number- 62885 reached at RHEL and then RHEL replied it back [Echo (ping) reply] successfully.

- 'TTL'  column shows the "Time to live" for a packet, its the number of hopes packet takes along the path till it reaches destination. At every hope TTL gets reduce by one till it reaches destination. So if we check the TTL in this case then when packet starts from Windows end its value is 128 and when it reached at RHEL end its value is 127 so packet is taking one hope in between/network while traveling from windows to RHEL system.


Now below is situation when ping packets got lost or possibly when you see "Request Time Out" in ping command output:

tcpdump_windows:
----------------
No.   Time             Frame Source                Destination        Protocol   Len    Seq-Number      TTL        Info
19    1.002995000         19 10.108.3.41           10.108.1.105          ICMP     74    62894 (0xf5ae)  128        Echo (ping) request
20    0.000262000         20 10.108.1.105          10.108.3.41           ICMP     74    62894 (0xf5ae)  63         Echo (ping) reply
24    0.957720000         24 10.108.3.41           10.108.1.105          ICMP     74    62895 (0xf5af)  128        Echo (ping) request  <---- no reply for this packet
25    4.857468000         25 10.108.3.41           10.108.1.105          ICMP     74    62896 (0xf5b0)  128        Echo (ping) request
26    0.000328000         26 10.108.1.105          10.108.3.41           ICMP     74    62896 (0xf5b0)  63         Echo (ping) reply
[...]
29    1.004176000         29 10.108.3.41           10.108.1.105          ICMP     74    62898 (0xf5b2)  128        Echo (ping) request
30    0.000269000         30 10.108.1.105          10.108.3.41           ICMP     74    62898 (0xf5b2)  63         Echo (ping) reply
31    1.003907000         31 10.108.3.41           10.108.1.105          ICMP     74    62899 (0xf5b3)  128        Echo (ping) request  <---- no reply for this packet
32    4.988263000         32 10.108.3.41           10.108.1.105          ICMP     74    62900 (0xf5b4)  128        Echo (ping) request
33    0.000287000         33 10.108.1.105          10.108.3.41           ICMP     74    62900 (0xf5b4)  63         Echo (ping) reply


linux.pcap
----------
No.   Time          Frame Source                Destination        Protocol   Len    Seq-Number      TTL        Info
21    1.003191         21 10.108.3.41           10.108.1.105          ICMP     74    62894 (0xf5ae)  127        Echo (ping) request
22    0.000039         22 10.108.1.105          10.108.3.41           ICMP     74    62894 (0xf5ae)  64         Echo (ping) reply
23    5.862365         23 10.108.3.41           10.108.1.105          ICMP     74    62896 (0xf5b0)  127        Echo (ping) request
24    0.000053         24 10.108.1.105          10.108.3.41           ICMP     74    62896 (0xf5b0)  64         Echo (ping) reply
[...]
27    1.004488         27 10.108.3.41           10.108.1.105          ICMP     74    62898 (0xf5b2)  127        Echo (ping) request
28    0.000035         28 10.108.1.105          10.108.3.41           ICMP     74    62898 (0xf5b2)  64         Echo (ping) reply
29    5.992547         29 10.108.3.41           10.108.1.105          ICMP     74    62900 (0xf5b4)  127        Echo (ping) request
30    0.000040         30 10.108.1.105          10.108.3.41           ICMP     74    62900 (0xf5b4)  64         Echo (ping) reply


- So here we see the problematic situation . As i have arrow pointed above, windows system did not got an reply of some packets , in those specific condition in ping output you can get "Request timed out" . Now the question is why there is no reply for those packets ?

- The sequence number of the first packet with no reply is 62895. If we try to find the packet with that sequence number at RHEL end then we will not find it, which means ping request packet with sequence number 62895 did not reached at RHEL system which means it got lost some where in network. Now in network as we have discussed above, packet is taking one hope (at some network device) so there is possibility that packets might be getting lost at that point/device.

- Same is the behavior for packet with sequence number  62899. It did not reached at RHEL system which means got lost somewhere in network.

So as i had explained before RHEL system is replying back properly for whatever packets are reaching till its end. Now if some packets after starting from windows are getting lost somewhere in network then you need to check this issue with your network team and its not an RHEL system issue.

Please help. THanks in advance.

• Edited by sanjeetkamble Saturday, May 10, 2014 7:05 AM

i have observe one more thing that is im also getting proper reply from windows server 2008 R2

the problem with only windows 8.1 pro & server 2012.

Kiindly do the needful

 

Hi,

from the output, the intermediate devies (router, switch, firewall) may discard the packets. please check them in detail. we recommend that involving devices vendors to confirm it if it is necessary.

Regards,

Mike

Hi,

Let me tell you, all systems are in same network there is no issue with device  (router, switch, firewall) we have already crosschecked with device vendor, Im not able to understand that all systems are in same network, if im getting proper response from one server where windows server 2008 R2 is installed, then why im getting drops on the system where server 2012 is installed.

i think the problem with OS only.

• Edited by sanjeetkamble 21 hours 31 minutes ago

Hi,

I will envolve another engineer to this thread, please be paint.

Hi,

if the two machines don't establish directly. all the traffic should go through switch first even though they are in the same network. when the packets reach at the switch, they will determine which port they should go according to the mac address table. if the destination address in the table, they will go to the corresponding port directly, if no address matches, they will go to switch trunk port.

if you suspect the os caused this issue. please try a clean boot on the windows server.

How to perform a clean boot in Windows

http://support.microsoft.com/kb/929135/en-us

Regards,

Mike

Hello,

i have given only 3 system for an example but there are around 60 client system (windows 8.1 pro) have same issue.

Till the observation only windows server 2008 R2 is getting proper ping response.  As you suggested we have perform clean boot but it didn't help me out.

Please look in to it