Are my iptables rules reasonable? [Resolved]

Thewyzewun · 10-03-2017, 09:37 AM

I'm a developer, and I use Docker.

Here's the output of `iptables -L`, I can't understand most of it, but it appears to be quite permissive.
I'm not running any services from my machine (not even SSH).

Code:

target     prot opt source               destination         
ACCEPT     all  --  anywhere             anywhere             ctstate RELATED,ESTABLISHED
ACCEPT     all  --  anywhere             anywhere            
INPUT_direct  all  --  anywhere             anywhere            
INPUT_ZONES_SOURCE  all  --  anywhere             anywhere            
INPUT_ZONES  all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere             ctstate INVALID
REJECT     all  --  anywhere             anywhere             reject-with icmp-host-prohibited

Chain FORWARD (policy DROP)
target     prot opt source               destination         
DOCKER-USER  all  --  anywhere             anywhere            
DOCKER-ISOLATION  all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere             ctstate RELATED,ESTABLISHED
DOCKER     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere             ctstate RELATED,ESTABLISHED
DOCKER     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere             ctstate RELATED,ESTABLISHED
DOCKER     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere             ctstate RELATED,ESTABLISHED
DOCKER     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere             ctstate RELATED,ESTABLISHED
DOCKER     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere             ctstate RELATED,ESTABLISHED
ACCEPT     all  --  anywhere             anywhere            
FORWARD_direct  all  --  anywhere             anywhere            
FORWARD_IN_ZONES_SOURCE  all  --  anywhere             anywhere            
FORWARD_IN_ZONES  all  --  anywhere             anywhere            
FORWARD_OUT_ZONES_SOURCE  all  --  anywhere             anywhere            
FORWARD_OUT_ZONES  all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere             ctstate INVALID
REJECT     all  --  anywhere             anywhere             reject-with icmp-host-prohibited

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         
OUTPUT_direct  all  --  anywhere             anywhere            

Chain DOCKER (5 references)
target     prot opt source               destination         

Chain DOCKER-ISOLATION (1 references)
target     prot opt source               destination         
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
DROP       all  --  anywhere             anywhere            
RETURN     all  --  anywhere             anywhere            

Chain DOCKER-USER (1 references)
target     prot opt source               destination         
RETURN     all  --  anywhere             anywhere            

Chain FORWARD_IN_ZONES (1 references)
target     prot opt source               destination         
FWDI_public  all  --  anywhere             anywhere            [goto] 
FWDI_public  all  --  anywhere             anywhere            [goto] 

Chain FORWARD_IN_ZONES_SOURCE (1 references)
target     prot opt source               destination         

Chain FORWARD_OUT_ZONES (1 references)
target     prot opt source               destination         
FWDO_public  all  --  anywhere             anywhere            [goto] 
FWDO_public  all  --  anywhere             anywhere            [goto] 

Chain FORWARD_OUT_ZONES_SOURCE (1 references)
target     prot opt source               destination         

Chain FORWARD_direct (1 references)
target     prot opt source               destination         

Chain FWDI_public (2 references)
target     prot opt source               destination         
FWDI_public_log  all  --  anywhere             anywhere            
FWDI_public_deny  all  --  anywhere             anywhere            
FWDI_public_allow  all  --  anywhere             anywhere            
ACCEPT     icmp --  anywhere             anywhere            

Chain FWDI_public_allow (1 references)
target     prot opt source               destination         

Chain FWDI_public_deny (1 references)
target     prot opt source               destination         

Chain FWDI_public_log (1 references)
target     prot opt source               destination         

Chain FWDO_public (2 references)
target     prot opt source               destination         
FWDO_public_log  all  --  anywhere             anywhere            
FWDO_public_deny  all  --  anywhere             anywhere            
FWDO_public_allow  all  --  anywhere             anywhere            

Chain FWDO_public_allow (1 references)
target     prot opt source               destination         

Chain FWDO_public_deny (1 references)
target     prot opt source               destination         

Chain FWDO_public_log (1 references)
target     prot opt source               destination         

Chain INPUT_ZONES (1 references)
target     prot opt source               destination         
IN_public  all  --  anywhere             anywhere            [goto] 
IN_public  all  --  anywhere             anywhere            [goto] 

Chain INPUT_ZONES_SOURCE (1 references)
target     prot opt source               destination         

Chain INPUT_direct (1 references)
target     prot opt source               destination         

Chain IN_public (2 references)
target     prot opt source               destination         
IN_public_log  all  --  anywhere             anywhere            
IN_public_deny  all  --  anywhere             anywhere            
IN_public_allow  all  --  anywhere             anywhere            
ACCEPT     icmp --  anywhere             anywhere            

Chain IN_public_allow (1 references)
target     prot opt source               destination         
ACCEPT     tcp  --  anywhere             anywhere             tcp dpt:ssh ctstate NEW
ACCEPT     udp  --  anywhere             224.0.0.251          udp dpt:mdns ctstate NEW

Chain IN_public_deny (1 references)
target     prot opt source               destination         

Chain IN_public_log (1 references)
target     prot opt source               destination         

Chain OUTPUT_direct (1 references)
target     prot opt source               destination

I have a good idea of how to configure iptables, on a machine running Ubuntu (using ufw) but little idea of how to do so on my development machine (where I believe the easiest interface I have at my disposal is iptables).

Help would be appreciated, coming up with some sensible settings

.

Basically, I want to be able to browse the Internet. I don't connect to any resources on my LAN (aside to the Internet, via WiFi).

hoes · 10-03-2017, 12:59 PM

Your results seem to complicated to type directly.
I suspect that this is also the result of a daemon like ufw.
So I would like for the daemon and edit the rules via the daemon.

The rules that you posted contain a lot of duplication and multiple rules that will never be reached.
So on its own it is not a good set of rules.

If want to learn more about iptables rules, I would suggest that you read the man page or google it. Understanding the rules is actually not that hard.

Thewyzewun · 10-06-2017, 08:24 AM

Quote:

Originally Posted by hoes

Your results seem to complicated to type directly.
I suspect that this is also the result of a daemon like ufw.
So I would like for the daemon and edit the rules via the daemon.

The rules that you posted contain a lot of duplication and multiple rules that will never be reached.
So on its own it is not a good set of rules.

If want to learn more about iptables rules, I would suggest that you read the man page or google it. Understanding the rules is actually not that hard.

Thanks for replying.

I've subsequently learned that my OS; Fedora, does not use iptables, but instead FirewallD.
So, these rules are not actually being used.

I've subsequently followed a couple of FirewallD tutorials, and improved my rules considerably.

hoes · 10-06-2017, 04:14 PM

You say that the rules are not used, but actually they are.
Both ufw and firewalld are convenience daemons that run on top of iptables.

If you would now look at the iptables rules you could probably recognise some of your rules.

Using firewalld is the right approach.
Glad you were able to configure the rules.