Instance cannot ping outside although compute node mgmt is pingable

asked 2014-12-08 17:36:06 -0500

nitins gravatar image

updated 2014-12-08 23:33:30 -0500

dbaxps gravatar image

HI I am using FlatDHCPManager to assign private IPs to VMs. I have a private network created for that.

I also have a public floating ip pool and VMs are pingable from outside using floating ip address.

I can also ping from inside the instance, compute node/controller mgmt ip as below, but I cannot ping the gateway ip for this subnet.

I don't know why I cannot access internet from instance when instance is accessible from outside.

[centos@dgdfdd ~]$ ping
PING ( 56(84) bytes of data.
64 bytes from icmp_seq=1 ttl=64 time=0.285 ms
64 bytes from icmp_seq=2 ttl=64 time=0.260 ms
--- ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1000ms
rtt min/avg/max/mdev = 0.260/0.272/0.285/0.020 ms
[centos@dgdfdd ~]$ ping
PING ( 56(84) bytes of data.
--- ping statistics ---
2 packets transmitted, 0 received, 100% packet loss, time 999ms

[centos@dgdfdd ~]$

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have you enabled dns and proper security group rules.

SGPJ gravatar imageSGPJ ( 2014-12-08 23:16:52 -0500 )edit

actually its because there is no source NAT happening for outgoing ICMP packets from the VM.

doing tcpdump on eth0 of the compute host I see following. The source ip is the private ip of the VM, 10:12:13.359045 IP > ICMP echo request, id 941, seq 26, length 6

nitins gravatar imagenitins ( 2014-12-09 18:03:48 -0500 )edit

Not sure how to get SNAT working without OVS as I am using nova-network. any suggesstions??

nitins gravatar imagenitins ( 2014-12-09 18:05:11 -0500 )edit