On Wed, 2017-08-16 at 10:18 +0530, Akshat Kakkar wrote: > On Mon, Aug 14, 2017 at 2:37 PM, Akshat Kakkar <akshat.1...@gmail.com> wrote: > > I have centos 7.3 (Kernel 3.10) running on a server with 128GB RAM and > > 2 x 10 Core Xeon Processor. > > I have hosted a webserver on it and enabled ssh for remote maintenance. > > Previously it was running on Centos 6.3. > > After upgrading to CentOS 7.3, occasionally (probably when number of > > hits are more on the server), I am not able to create new connections > > (neither on web nor on ssh). Existing connections keeps on running > > fine. > > > > I did packet capturing using tcpdump to understand if its some > > intermediate network issue. > > What I found was the server is not replying for new SYN requests. > > > > So it's clear that its not at all application issue. Also, there are > > no logs in applications logs for any connections dropped, if any. > > > > I check my firewall rules if there is some rate limiting imposed. > > There is nothing in there. > > > > I check tc, if by mistake some rate limiting is imposed. There is > > nothing in there too. > > > > I have increased noOfFiles to 1000000 and other sysctl parameters, but > > the issue is still there. > > > > Has anybody experienced the same? > > > > How to go about? Anybody ... Please Help!!! > > Its getting lonely out here. Anybody there ???
We wont help you unless you use a recent kernel. 3.10 misses all recent improvements in TCP stack (4 years of hard work)
