Really struggling to pin point a network gateway issue in EC2.
I've set a new machine. Exact same Security groups, subnet and VPC setup as previous one and am trying to ping third machine..
Tcp dump from the 3rd server shows similar response from these two machines I am comparing:
$> tcpdump -qtln icmp listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes IP NEW_MACHINE > THIRD_MACHNE: ICMP echo request, id 2750, seq 1, length 64 IP THIRD_MACHNE > NEW_MACHINE: ICMP echo reply, id 2750, seq 1, length 64 IP OLD_MACHINE > NEW_MACHINE: ICMP echo request, id 63237, seq 1, length 64 IP NEW_MACHINE > OLD_MACHINE: ICMP echo reply, id 63237, seq 1, length 64
iptables are empty (iptables -L).
When I ping from
old machine, I get back a response and all is well, from the new machine, 100% packet loss:
[root@ansible-1-1b network-scripts]# ping -v THIRD_MACHINE PING THIRD_MACHINE (THIRD_MACHINE) 56(84) bytes of data. ^C --- THIRD_MACHINE ping statistics --- 16 packets transmitted, 0 received, 100% packet loss, time 15365ms
These are EC2 machines, in same VPC and as far as I can tell Ec2 config is similar (same vpc, same security groups, no specific rules for either machines) Any ideas where I should next be looking at?
The one major diff I see is the working machine:
uname -r 2.6.32-696.6.3.el6.x86_64
vs the failing one:
uname -r 4.9.43-17.39.amzn1.x86_64
Security Groups from AWS, for the two pinging machines: Client security group
On the target machine: Server sg setup
Maybe a new flag I am missing?
For what it's worth I use ping for the test, but SSH is timing out just as well.