VMware tools wouldn't have anything to do this. It's an optional package.
You say it's not the firewall because you stopped it with
service iptables stop. Still, I would try
iptables -F, which will flush all rules (until you reload the saved config).
Here are some questions / things to try:
1 - Which machine are you pinging from? Is it also on the same ESXi host, or outside the ESXi's virtual switch? What happens when you ping it from another virtual machine on the same host?
2 - What happens when you try to ping something else from this VM?
3 - What does a traceroute show to/from the VM?
4 - Do you have any VLAN id's configured?
5 - Does the MAC address listed in
/etc/sysconfig/networking-scripts/ifcfg-eth0 match the adapter mentioned in VM -> Edit Settings?
6 - What Ethernet driver do you have configured for the VM?
7 - Have you tried installing a fresh VM?