--- Al Sparks <data345@xxxxxxxxx> wrote:
> This is a standard RedHat / CentOS firewall configuration, where I
> told it, through the standard RH setup GUI, that I want ssh and
> snmp allowed through.
>
> Chain INPUT (policy ACCEPT)
> target prot opt source destination
> RH-Firewall-1-INPUT all -- anywhere anywhere
>
> Chain FORWARD (policy ACCEPT)
> target prot opt source destination
> RH-Firewall-1-INPUT all -- anywhere anywhere
>
> Chain OUTPUT (policy ACCEPT)
> target prot opt source destination
>
> Chain RH-Firewall-1-INPUT (2 references)
> target prot opt source destination
> ACCEPT all -- anywhere anywhere
> ACCEPT icmp -- anywhere anywhere icmp any
> ACCEPT ipv6-crypt-- anywhere anywhere
> ACCEPT ipv6-auth-- anywhere anywhere
> ACCEPT udp -- anywhere 224.0.0.251 udp dpt:5353
> ACCEPT udp -- anywhere anywhere udp dpt:ipp
> ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
> ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:snmp
> ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:ssh
> REJECT all -- anywhere anywhere reject-with icmp-host-prohibited
>
> The way I read this, though, the first rule in the RH-Firewall-1-INPUT
> chain applies to all packets coming in, which it accepts. That's all
> protocols from "anywhere" going to "anywhere".
>
> So shouldn't the packet no longer be evaluated past that rule?
>
> I know that when I have this enabled, it's stopping packets. So I'm
> reading this wrong. What am I getting wrong?
>
> === Al
I found the answer to my own question. The above output is from a
# iptables -L
But I looked at the /etc/sysconfig/iptables file and:
-A FORWARD -j RH-Firewall-1-INPUT
-A RH-Firewall-1-INPUT -i lo -j ACCEPT
-A RH-Firewall-1-INPUT -p icmp --icmp-type any -j ACCEPT
-A RH-Firewall-1-INPUT -p 50 -j ACCEPT
-A RH-Firewall-1-INPUT -p 51 -j ACCEPT
-A RH-Firewall-1-INPUT -p udp --dport 5353 -d 224.0.0.251 -j ACCEPT
-A RH-Firewall-1-INPUT -p udp -m udp --dport 631 -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 161 -j ACCEPT
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A RH-Firewall-1-INPUT -j REJECT --reject-with icmp-host-prohibited
COMMIT
The first RH-Firewall-1-INPUT only applies to "-i lo" or the loopback interface.
Strangely enough, that's not reflected in the
# iptables -L
output.
=== Al
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