I agree this is becoming increasingly necessary as vendors turn to AWS for hosting services and IP addressing becomes less static for services.

Supporting a hostname typically results in a DNS lookup at the time of rule creation and then no change until the rule is reloaded. As a work-around to this some distributions reload hostname-based rules every 5 min while others do so daily.

This still has some caveats however: In one example a DNS record which is more dynamic has makes use of a low TTL may change more frequently than the update interval. In another a lookup which returns multiple A records presumably would be expected to generate multiple firewall rules while many implementations may only select the first response. There are other assumptions made on behavior by the user (how are CNAMEs handled?).

To implement this in VyOS the right way would be non-trivial and require a bit of development. I would suggest the use of VyOS-generated address-group (ipset) which is populated and updated by a background process which keeps track of TTL values.

Syntax-wise this could be placed under the umbrella of a new firewall group type e.g. "name-group". Members of a name-group would be a FQDN. A daemon (or routine cron) handle resolving the FQDN(s) into the IP(s) associated while also tracking the TTL. On update new entries would be added but old entries would not be removed until their TTL expired.

Configuration would look something like:

set firewall group name-group NAME-EXAMPLE name 'www.example.com'
set firewall group name-group NAME-EXAMPLE name 'example.com'

set firewall name LAN-OUT rule 100 destination group name-group NAME-EXAMPLE

This would allow name-based functionality to be implemented in the way users often assume is the case despite known caveats and limitations typically encountered in other implementations.

Other enhancements could include DNSSEC support where one a key is learned it is added to the group configuration and enforced unless overridden.

A mock-up of this has been on my to-do list but unfortunately I have not had the time. Is anyone familiar with an existing project which might already do this or something similar?

+1 for 1.4

PR https://github.com/vyos/vyos-1x/pull/1327

set firewall group domain-group DOMAINS address 'example.com'
set firewall group domain-group DOMAINS address 'example.org'
set firewall name FOO default-action 'accept'
set firewall name FOO rule 10 action 'drop'
set firewall name FOO rule 10 source group domain-group 'DOMAINS'
set interfaces ethernet eth0 firewall local name 'FOO'

Fix smoketest https://github.com/vyos/vyos-1x/pull/1352

1. Some domains can't be added, for example dns.google

vyos@r12# set firewall group domain-group DOMAINS address dns.google

  
  
  Invalid value
  Value validation failed
  Set failed

[edit]
vyos@r12# 

vyos@r12# set firewall group domain-group DOMAINS address dns.google.com
[edit]
vyos@r12#

2. Set Domain group without address Fails

vyos@r12# set firewall group domain-group DOMAIN
[edit]
vyos@r12# commit
[ firewall ]
VyOS had an issue completing a command.

Traceback (most recent call last):
  File "/usr/libexec/vyos/conf_mode/firewall.py", line 458, in <module>
    apply(c)
  File "/usr/libexec/vyos/conf_mode/firewall.py", line 426, in apply
    for address in group_config['address']:
KeyError: 'address'



[[firewall]] failed
Commit failed
[edit]
vyos@r12#

Fix Regex for addresses and python ckecks https://github.com/vyos/vyos-1x/pull/1354

Still on track for 1.4 ?

PR: https://github.com/vyos/vyos-1x/pull/1633

Adds firewall node rule N source/destination fqdn domain.com for single domains per rule and refactors resolver daemon.

How far are we in the testing of this important feature ?

In T970#149229, @olivier.hault wrote:

How far are we in the testing of this important feature ?

Try it with groups

set firewall group domain-group domains address example.com
set nat source rule 100 destination group domain-group domains

I tested this feature with the following firewall config:

set firewall group domain-group DG_TEST address 'nu.nl'
set firewall group domain-group DG_TEST address 'www.nu.nl'
set firewall interface eth1 out name 'ETH1_OUT'
set firewall name ETH1_OUT default-action 'accept'
set firewall name ETH1_OUT rule 10 action 'drop'
set firewall name ETH1_OUT rule 10 destination group domain-group 'DG_TEST'

When I try to connect to the dutch news site, it is denied:

vyos@R1:~$ ping nu.nl
PING nu.nl (104.110.191.44) 56(84) bytes of data.
^C
--- nu.nl ping statistics ---
20 packets transmitted, 0 received, 100% packet loss, time 19487ms

And I see packets matching the firewall rule on the VyOS router:

vyos@R4:~$ show firewall name ETH1_OUT
Ruleset Information

---------------------------------
IPv4 Firewall "ETH1_OUT"

Rule     Action    Protocol      Packets    Bytes  Conditions
-------  --------  ----------  ---------  -------  -------------------
10       drop      all                46     3336  ip daddr @D_DG_TEST
default  accept    all               127     8669

Tested on VyOS 1.4-rolling-202307040317.

It seems to work as expected for me.

R1 is a VyOS router behind R4, which is what I had running in a lab when trying this.

It won't be implemented for 1.3

Any updates ?

In T970#177580, @olivier.hault wrote:

Any updates ?

Which updates? Did you try the current implementation?

I'm not sure if this has been included in version 1.4 or not?

In T970#177585, @olivier.hault wrote:

I'm not sure if this was been included in version 1.4 or not?

Yes, it was included in 1.4

Perfect, would it be possible to update https://docs.vyos.io/en/sagitta/changelog/1.4.html and doc pages like https://docs.vyos.io/en/sagitta/configuration/firewall/groups.html accordingly ?