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dannymcc
Asked: 2013-03-05 06:09:33 +0800 CST

UFW Firewall Rules ordering?

  • 772

I have the following rules on our server within UFW:

To                         Action      From
--                         ------      ----
22                         ALLOW       217.22.12.111
22                         ALLOW       146.200.200.200
80                         ALLOW       Anywhere
443                        ALLOW       Anywhere
22/tcp                     ALLOW       109.104.109.0/26

The first two rules are our internal IP's which we want to ensure can always SSH in (port 22). The next two rules are to allow HTTP and HTTPS viewing from any IP addresses anywhere. The final rule is to allow SSH from our code deployment system.

I set a ufw default deny rule up but it doesn't appear to be showing. Should I also have a final rule which denies everything?

If I add a deny everything rule, does the order the rules appear above make a difference? Presumably if this list gets longer adding another allow rule above a deny rule is impossible, meaning I'll have to remove and re-add some rules?

ubuntu

3 Answers

  1. If you're interested in reordering your UFW rules, this is one way to do it.

    $ sudo ufw status numbered

     To                         Action      From
     --                         ------      ----
[ 1] 22                         ALLOW IN    Anywhere
[ 2] 80                         ALLOW IN    Anywhere
[ 3] 443                        ALLOW IN    Anywhere
[ 4] 22 (v6)                    ALLOW IN    Anywhere (v6)
[ 5] 80 (v6)                    ALLOW IN    Anywhere (v6)
[ 6] 443 (v6)                   ALLOW IN    Anywhere (v6)
[ 7] Anywhere                   DENY IN     [ip-to-block]

    Say you accidentally added a rule to the end, but you wanted up top.

    First you will have remove it from the bottom (7) and add it back.

    $ sudo ufw delete 7

    Note, be careful of removing multiple rules one after another, their position can change!

    Add back your rule to the very top (1):

    $ sudo ufw insert 1 deny from [ip-to-block] to any
    • 58

  2. The command ufw status verbose will show you the default rule. For your configuration you probably want it to say

    Default: deny (incoming), allow (outgoing)

    In that case, you don't need a separate 'deny everything' rule, and the order of your other rules doesn't matter. If you do want to change the order, you can add a rule at a specific place by using ufw insert [position] [rule text]. You can get a numbered list of rules with ufw status numbered.

    • 16

  3. If you are familiar with the format of the rules generated by iptables-save command, you can just edit the config files for ufw in /etc/ufw/user.rules and /etc/ufw/user6.rules. Even if you aren't, for every user added rule there is a comment showing the matched ufw command for your reference.
    Change the orders as you desire, and save it. Then run sudo ufw reload, the new order will be in place.
    This way is quicker than delete and insert commands, but you probably should backup before editing if you are not very confident.

    • 8