On 12/07/16 18:20, Jeff White wrote:
On CentOS 7 with firewalld I have a box with numerous
interfaces acting as a NAT gateway. This works but I
noticed that it routes/forwards traffic not just from my
internal zone to external zone but also between interfaces
within the internal zone. How can I prevent that traffic?
I've tried adding direct and rich rules to deny the
traffic but it doesn't work. Direct:
firewall-cmd --direct --add-rule ipv4 filter INPUT 0 -s
10.110.4.0/22 -d 10.110.0.0/22 -j REJECT
That command works, and I see it in `iptables -L` but
traffic is still allowed. Rich:
# firewall-cmd --zone=trusted --add-rich-rule='rule
family=ipv4 source address=10.110.4.0/22 destination
address=10.110.0.0/22 reject'
Error: INVALID_RULE: destination action
I can't find any explanation of what that error means.
So, how do you tell firewalld to stop forwarding traffic
between interfaces?
# firewall-cmd --get-active-zones
public
interfaces: ens161 ens193
trusted
interfaces: ens192 ens224 ens256 lo
# firewall-cmd --list-all
public (default, active)
interfaces: ens161 ens193
sources:
services: dhcpv6-client ssh
ports:
masquerade: yes
forward-ports:
icmp-blocks:
rich rules:
yes, to me too it sort of defines basic logic - one would
expect to be able with a "rich rule" to block/ban a host
(actually there are quite few articles on the net stating it
should be doing that)
public (active)
interfaces: em3
sources:
services: dhcpv6-client ssh
ports:
masquerade: yes
forward-ports:
icmp-blocks:
rich rules:
rule family="ipv4" source address="192.168.2.0/24"
reject
yet host from 192.168.2.0/24 (which is firewalld's zone
work) are able to masquerade and access all (in this case
whole Internet) behind em3 interface.
It smells like a bug to me.
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