I have a problem with my networking performance. I am using Ubuntu 16.04 on VMware Cloud Server with NIC E1000. But I see some packets dropped in sections of ifconfig command:
root@ubuntu:~# ifconfig ens192
ens192 Link encap:Ethernet HWaddr 00:50:56:03:25:14
inet addr:192.16.1.100 Bcast:192.16.1.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:574749 errors:0 dropped:83 overruns:0 frame:0
TX packets:76478 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:44109471 (44.1 MB) TX bytes:19484534 (19.4 MB)
Although it just some packets dropped but my server is running a real-time game online, so you know it impacts my clients that are connecting to it.
I have done in some researching and exploring information on Google, after that I tried to change config file for buffer ring, max windows size, and so on. But it still drops my packets.
So, now I want to capture packets that dropped for analyzing what type of packets exactly it is.
I also tried this capture for my view in wireshark:
sudo tcpdump -i ens192 -n -w /var/www/html/logs.pcap -C 1 -Z root
But I don't think I can see what packets are dropped! I think packets dropped is ignored before going to the filter of tcpdump.
Can you suggest me what method to capture "dropped packets" above (dropped:83)?
Thanks in advance!
iptables
for that information. see serverfault.com/a/126078 and serverfault.com/q/385937ethtool -S ens192
based on this answer. There can be any number of reasons your interface is dropping packets. May want to also check your outbound switchport to see if it is also detecting dropped/error packets in or out. Malformed and packets that fail checks can be dropped.