Opening port 80 on Oracle Cloud Infrastructure Compute node [closed] - oracle-cloud-infrastructure

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This is an elementary question however one I cannot seem to resolve by perusing the Oracle Cloud Infrastructure documentation. I've created an Ubuntu-based compute node, and it's attached to a subnet. In that subnet I've created a stateful rule with source 0.0.0.0/0, IP protocol: TCP, Source Port Range: All, Destination Port Range: 80.
There is no firewall configured on the server.
Despite this configuration I can't access the compute node's public IP. Any ideas?

Answer 1

I figured it out. The connectivity issue was due to Oracle's default use of iptables on all Oracle-provided images. Literally the very first thing I did when spinning up this instance was check ufw, presuming there were a few firewall restrictions in place. The ufw status was inactive, so I concluded the firewall was locally wide open. Because to my understanding both ufw and iptables look at the netfilter kernel firewall, and because ufw is the de facto (standard?) firewall solution on Ubuntu, I've no idea why they concluded it made sense to use iptables in this fashion. Maybe just to standardize across all images?
I learned about the rules by running:
$ sudo iptables -L
Then I saved the rules to a file so I could add the relevant ones back later:
$ sudo iptables-save > ~/iptables-rules
Then I ran these rules to effectively disable iptables by allowing all traffic through:
$ iptables -P INPUT ACCEPT
$ iptables -P OUTPUT ACCEPT
$ iptables -P FORWARD ACCEPT
$ iptables -F
To clear all iptables rules at once, run this command:
$ iptables --flush
Anyway, hope this helps somebody else out because documentation on the matter is non-existent.

Answer 2

When deploying compute instances at Oracle Cloud Infrastructure you need to take into account few things:
Create Internet Gateway (IGW).
Define routes to point to IGW.
Allow port 80 in the Security List associated with the IGW. By default you only have access to SSH and ICMP 3,4 type.
Allow connectivity on Compute's instance firewall (which is enabled by default).
In your example if you are using a OEL shape:
$ sudo firewall-cmd --zone=public --permanent --add-port=80/tcp
$ sudo firewall-cmd --reload

Answer 3

Always refer to the official guide: https://docs.cloud.oracle.com/en-us/iaas/developer-tutorials/tutorials/apache-on-ubuntu/01oci-ubuntu-apache-summary.htm
$ sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 80 -j ACCEPT
$ sudo netfilter-persistent save
$ sudo systemctl restart apache2

Answer 4

credited to https://medium.com/#fathi.ria/oracle-database-cloud-open-ports-on-oci-1af24f4eb9f2
Coumputer Instance(Such as Ubuntu) -> Virtual Cloud Network -> Security List -> Ingress Rules -> Please add a rule to allow access to port 80 from anywhere

Answer 5

Pre-Requisite
VM instance should have been created and running
Access to Public and Private keys used during the creation of VM instance
Log into the VM using SSH and run the following command
$ sudo iptables --list --line-numbers
It will show the details about Chain INPUT (policy ACCEPT). From the list
required to Delete REJECT all rule in the IPTABLES.
$ sudo iptables -D INPUT <Reject Line number>
e.g.
$ sudo iptables -D INPUT 6
Check if the REJECT rule is deleted
sudo iptables --list --line-numbers
Access the Default Security List and Edit Ingress Rules to Allow Internet Traffic on Port
Edit the INGRES Rule Add CIDR 0.0.0.0/0 TCP Destination 9999
(N): Networking >Virtual Cloud Networks> Virtual Cloud Network Details>Security Lists> Security List Details
Access your application via web browser
Type http://<public IP address of the VM>:port

Answer 6

I guess if you add the rule below to your iptables it should work; otherwise you'll be disturbing other rules which are related to block volume attachment that comes preconfigured on those Oracle images.
iptables -I INPUT 5 -i ens3 -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT

Answer 7

If you have not created Internet Gateway yet, that might be the reason. In order to connect the VCN with the public internet you need to have an Internet Gateway and a route table to direct the traffic through the gateway.