Access internet from instance
On this moment i have my OpenStack environment running. I am testing connectivity from an instance. The instance i have chosen is a Ubuntu cloud instance. The problem is: I can's get apt to work from this instance. Ping to an url on the internet works. I can ssh to this instance.
On this moment, wget a file from the internet doesn't work either:
"Connecting to speedtest.dal01.softlayer.com (speedtest.dal01.softlayer.com)|74.86.116.210|:80... connected.
HTTP request sent, awaiting response..."
The HTTP-request is sent but it seems it can's return.
So i guess this is a problem with the secgroup. I opened port 80 and port 22 for this instance. In a nmap scan from another computer i get port 22 open, but port 80 closed. The iptables on the instance is empty. I also flushed it again.
nmap port scan of the instance :
PORT STATE SERVICE
22/tcp open ssh
80/tcp closed http
does anyone have any idea? Thanks you!
Maybe you have a wrong MTU size, are you using vxlan or gre tunnels? check what mtu size have your instance with ip a
Hi Eduaro, I am using GRE tunnels. The command "ip a" returns MTU 1500 on the instance on interface eth0.
GIve mtu to 1454 with:
If that solves your problem, change mtu size at dnsmask file at /etc/neutron/, if not, that will be another issue.
Regards
Thank you for your reply Eduaro,
Is there any difference in using MTU 1400 and MTU 1454 for eth0? (see answer below)
Theoretically there is a difference,a networking expert guy would say that. For a PoC, it just simply works! The difference is the frame bits reserved for encapsulation, probably there is a performance issue have the wrong mtu. If there is a networking expert, correct me please.