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After successfully setting up a base Linux server in the cloud using the Base ServerTemplate for Linux (Chef) tutorial, you may need to perform the following common administrative operations.
Note: For more information on iptables, refer to Linux documentation.
When iptables is enabled, which is the default behavior in all Linux-based v12 ServerTemplates, TCP ports 22, 80, and 443 are configured to be open to any IP address in order to enable minimum functionality and access. If you want to add or remove a firewall rule on a running (operational) server by opening or closing a port, you can set the following inputs accordingly and run the sys_firewall::setup_rule operational script.
If you want the firewall rules to be set at boot time, you can either add the Chef recipe to the end of the boot script list or update the sys_firewall::default recipe to change the list of default firewall permissions by explicitly opening up additional ports. However, you should only consider overriding the default recipe if you want to change the default behavior for all of your servers that use that cookbook.
Note: If the cloud provider supports security groups, you must also open or close the appropriate ports in the security group resource.
|Input Name||Description||Example Value|
|Firewall Rule Port||Specify the port number to open or close.||text: 8080|
|Firewall Rule|| |
Defines whether you are creating or removing a firewall permission for the specified port (Firewall Rule Port) over the specified IP protocol (Firewall Rule Protocol), as restricted by the specified IP range (Firewall Rule IP Address).
|Firewall Rule IP Address|| |
Use CIDR notation to define the range of IP addresses that will either be allowed or denied access to the specified port (Firewall Rule Port) over the specified IP protocol (Firewall Rule Protocol).
Leave this value set to "any" (default) to allow access from any IP address (0.0.0.0/0). Use an exclamation point (!) before the IP address specification to deny access (i.e. "blacklist") from a specific IP address (e.g. !184.108.40.206) or IP range (e.g. !220.127.116.11/24)
|Firewall Rule Protocol|| |
Specify the Internet protocol for the specified port (Firewall Rule Port).
For troubleshooting and security purposes, you may want to list a server's current firewall rules to make sure that a server has the expected IP/port permissions. This script is especially useful if you want to check the firewall rules across all servers in a deployment to validate that all of them have the same iptables rules.
22:25:03: ==================== do_list_rules : Firewall rules Begin ================== Chain INPUT (policy ACCEPT) target prot opt source destination FWR all -- 0.0.0.0/0 0.0.0.0/0 Chain FORWARD (policy ACCEPT) target prot opt source destination Chain OUTPUT (policy ACCEPT) target prot opt source destination Chain FWR (1 references) target prot opt source destination ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED ACCEPT icmp -- 0.0.0.0/0 0.0.0.0/0 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:22 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:443 ACCEPT tcp -- 10.123.456.22 0.0.0.0/0 tcp dpt:8000 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpt:80 REJECT tcp -- 0.0.0.0/0 0.0.0.0/0 tcp flags:0x16/0x02 reject-with icmp-port-unreachable REJECT udp -- 0.0.0.0/0 0.0.0.0/0 reject-with icmp-port-unreachable ==================== do_list_rules : Firewall rules End ====================
If you want to perform the same action via SSH, follow the steps below.
# sudo -i
# /sbin/iptables -L
Iptables is typically enabled by default ('Firewall' = enabled). However, you can use the following script to enable or disable Iptables on an instance.
Warning! You should only perform this action if you fully understand its implications. For example, if the cloud provider does not support cloud-level firewall services such as security groups, you could permanently lock yourself out of the instance if you disable Iptables.
To enable Iptables, follow the steps below.
To disable Iptables, follow the steps below.
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