Can access host only if I PING

[Terry_Roman]

Hi all, I have network issue, I can access centos 7 x64 host only if I start ping. If ping is off host is not accesable on any port. If I first ping Host then evrything works, HTTP, ssh, telnet.
It's a local network, internet is working, firewalld is disabled, selinux disabled.
There is only 2 hosts have eccess without ping, my dns server and gateway host.
This two hosts listed in network config and I think this is a reason why they have access without ping.
Thank you in advance.

[hunter86_bg]

This sounds like your switch's CAM table gets empty, and once you ping, the switch broadcasts the ICMP echo request on all ports and once the CentOS 7 responds - you get your connection requests properly.

This is just a guess.
In order to verify that, run tcpdump on the CentOS and then try to connect via ssh/http or any other service on your CentOS. If the CentOS doesn't respond , but a package is received you have to check local firewall and ignore my "guess".

[TrevorH]

Also post the ifcfg file for the interface from your CentOS box as the networking is meant to use arp to tell the switch it exists as it boots.