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