Thanks for the reply.
This is near enough what I posted on GNS3.
I’m experiencing a similar problem to GNS3 • Login
If I connect a cloud (bound to my NIC) and link to a router, everything works fine.
If I create a virtual switch between my router and cloud then I get intermittent pings. Some pings will time out, some will reply.
I have had the same intermittent ping when I connect a loopback to a virtual switch. Also I have tried connecting a Linksys wireless NIC to a virtual switch and get the same issues.
However, if I connect direct to the virtual router from cloud wireless or cloud loopback or cloud Realtek NIC it works OK.
Running Windows 7 64bit. Realtek PCIe GBE RTL8167.
I couldn’t even get any traffic through until I found the fixes from various threads about disabling:
IPv4 Checksum Offload (disabled)
Large Send Offload (disabled)
TCP Checksum Offload (disabled)
UDP Checksum Offload (disabled)
As Wireshark was showing incorrect checksums.
Show mac on the switch displays the correct MAC for router and NIC. Also arp table on router shows correct MAC for NIC.
Wireshark capturing on real NIC of PC shows ICMP echo then eventually a reply.
Its strange that it works using a cloud connection direct to router but not direct to switch.
I need to keep my firewall running. I have tried allowing all on the firewall but to no avail. This is the REAL world connection for my virtual routers so I need to use this NIC.
Created a loopback adapter in Windows (no IP address - IP assigned via DHCP). Bridged this with my LAN adapter. The bridged connection STILL has Comodo driver enabled. BUT it now works… 1 way.
I can ping from PC to virtual router but not the other way round.
My only option seems to be to disabled the Comodo driver on the NIC to get traffic flowing properly.