I'm not 100% this is a KVM issue but I have a server with a couple of virtual machines installed that will not respond to pings. The configuration is as follows:
In this configuration neither eth5 nor vmbr1 respond to pings from outside the vlan. I did a tcpdump on incoming and outgoing icmp requests for eth5 and found that although the pings are getting TO the server, the server does not send a response. I am able to ping everything on the vlan except for this host from outside.
Code:
|--------------| |------------------|
|Host eth5 | | |
| 192.168.1.45 | | Bridged eth3 |
|--------------| |------------------|
|
|
|------------------|
| vmbr1 |
| 192.168.1.30 |
|------------------|
|
|
|------------------|
| guests |
|------------------|