angico wrote:
GREAT, GUYS! IT WORKED!!!!!! I THANK YOU VERY MUCH for the help!
angico.
Well the problem is in your rules in the first place, I cannot beleive
no one caught this.
Let's reiterate your rules:
1 ACCEPT all -- 192.168.0.0/24 boitata.jlm
2 ACCEPT tcp -- anywhere anywhere state RELATED,ESTABLISHED
3 ACCEPT udp -- anywhere anywhere udp spt:domain
4 ACCEPT udp -- anywhere anywhere udp spt:http state NEW,RELATED,ESTABLISHED
5 ACCEPT icmp -- anywhere anywhere icmp echo-reply
6 ACCEPT icmp -- anywhere anywhere icmp echo-request
(by the way, next time post the output of iptables-save, much better readable)
In rule 2, you allow all packets that are tcp and belong to an established
session or related session. This means you DON'T allow the ICMP fragmentation
needed messages in (dunno if they are deemed related or established, I think
the latter). This is where you shoot yourself in the foot. This is why you SEEM
to need the clamp-mss option. You don't need that option, your rules are faulty.
Nothing to do with your problem, but let's have a quick look at your other
rules:
1) I prefer to match by interface, but YMMV.
3) Only sensible if you run a local nameserver.
4) What does this do?
6) This rule would not be needed had you allowed all RELATED and ESTABLISHED
packets in.
I won't go into your OUTPUT rules, they should work together with your input
rules.
What you probably want is something like this:
# Default is to drop
-P INPUT DROP
# Let in anything established or related
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
# anything not new is dropped right away
-A INPUT -m state ! --state NEW -j DROP
# pings are allowed
-A INPUT -p icmp --type echo -j ACCEPT
# Input from the local network is allowed
-A INPUT -i $LOCALIF -j ACCEPT
# anything else is logged and dropped by the policy
-A INPUT -j LOG
# We allow anything from the box itseld to the outside
-P OUTPUT ACCEPT
(Add approptiate logging rules for safety and debugging)
I think you would do well to read some tutorials on writing IP tables rules.
HTH,
M4
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