Ok, I'm working with an OpenWRT router. I have the following iptable rules:
iptables -t nat -I prerouting_rule -m mac --mac-source $2 -p tcp --dport 80 -j DNAT --to-destination $3:80;
iptables -t nat -I prerouting_rule -m mac --mac-source $2 -p tcp --dport 443 -j DNAT --to-destination $3:80;
These rules effectively redirect traffic on ports 80 and 443 to a specific destination ip address for a specific requesting MAC address.
I'd like to add another rule (or set of rules if necessary) that will drop traffic on all other ports for this specific MAC without breaking these 2 rules.
My version of iptables is: v1.4.10
Any pointers would be greatly appreciated!
EV
iptables -t nat -A prerouting_rule -m mac --mac-source $2 -j DROP
generally: use -A instead -I, append is more "human"
edit:
you should filter out pacakages in the filter tables ;)
iptables -A FORWARD -m mac --mac-source $2 --dport 80 -j ACCEPT
iptables -A FORWARD -m mac --mac-source $2 --dport 443 -j ACCEPT
iptables -A FORWARD -m mac --mac-source $2 -j DROP
i forgot that not all tables can do anything...
Related
I'm using NAT mode for guest networking. I need my machines to be accessible from outside the guest. I've set up iptables to port forward a specific port on host to port 22 on guest, but this does not seem to work.
I added this rules:
# Port Forwardings
-A PREROUTING -i eth0 -p tcp --dport 9867 -j DNAT --to-destination 192.168.122.136:22
# Forward traffic through eth0 - Change to match you out-interface
-A POSTROUTING -s 192.168.1.0/24 -o eth0 -j MASQUERADE
When I ssh 192.168.122.136 from host it works perfectly, however when I try ssh 192.168.122.136 -p 9867 it shows ssh: connect to host 192.168.122.1 port 9867: Connection refused
I've enabled port forwarding on /etc/ufw/sysctl.conf
using iptables -t nat -L shows that the rule is set up on iptable
DNAT tcp -- anywhere anywhere tcp dpt:9867 to:192.168.122.136:22
Found my answer here. basicly I changed the above to
# connections from outside
iptables -t nat -A PREROUTING -p tcp --dport 9867 -j DNAT --to 192.168.122.136:22
# for local connection
iptables -t nat -A OUTPUT -p tcp --dport 9867 -j DNAT --to 192.168.122.136:22
# Masquerade local subnet
iptables -t nat -A POSTROUTING -s 192.168.122.0/24 -j MASQUERADE
iptables -A FORWARD -o virbr0 -m state --state RELATED,ESTABLISHED -j ACCEPT
iptables -A FORWARD -i virbr0 -o eth0 -j ACCEPT
iptables -A FORWARD -i virbr0 -o lo -j ACCEPT
I have the following rule in my iptables that redirects port 5060 to 5065.
-A PREROUTING -i eth0 -p udp -m udp --dport 5060 -j REDIRECT --to-ports 5065
I 'd like to apply this rule for several external IPs only, e.g. for example, to 123.123.123.123 and 124.124.124.124 only.
I added the following rule instead of above:
-A PREROUTING -s 123.123.123.123 -i eth0 -p udp -m udp --dport 5060 -j REDIRECT --to-ports 5065
But then when I tried to add the next rule:
-A PREROUTING -s 124.124.124.124 -i eth0 -p udp -m udp --dport 5060 -j REDIRECT --to-ports 5065
I got the following message:
iptables: No chain/target/match by that name
How to put these rules properly?
Thank you in advance,
For preprouting and postrouting you have t specify that you are working on the NAT chain.
ie :
iptables -t nat -A PREROUTING -s 124.124.124.124 -i eth0 -p udp -m udp --dport 5060 -j REDIRECT --to-ports 5065
I like to create a simple captive portal that works for an interface that is part of a bridge.
The bridge interface br0 (10.19.1.1/16) consists of two interfaces eth0 and eth1.
Behind eth1 are the client computers. Behind eth0 is a switch that has the internet gateway connected to.
For the captive portal, all tcp requests to port 80 coming from the clients behind eth1 need to be directed the local web server.
The following lines seem to work as the website request are redirected to the local web server. The problem is that once the authentication line below is used, the client cannot load any regular websites anymore.
I have already searched the internet but haven't found a solution.
PORTAL_INT="eth1"
PORTAL_IP="10.19.1.1"
#'drop' packets from being bridged
ebtables -t broute -A BROUTING -i $PORTAL_INT -p IPv4 --ip-proto tcp --ip-dport 80 -j redirect --redirect-target DROP
iptables -N internet -t mangle
iptables -t mangle -A PREROUTING -j internet
#authenticated
#iptables -t mangle -I internet 1 -m mac --mac-source $CLIENT_MAC -j RETURN
#mark all traffic
iptables -t mangle -A internet -j MARK --set-mark 99
#redirect website access
iptables -t nat -A PREROUTING -m mark --mark 99 -p tcp --dport 80 -j DNAT --to-destination $PORTAL_IP
iptables -t filter -A FORWARD -m mark --mark 99 -j DROP
iptables -t filter -A INPUT -p tcp --dport 80 -j ACCEPT
iptables -t filter -A INPUT -p udp --dport 53 -j ACCEPT
iptables -t filter -A INPUT -m mark --mark 99 -j DROP
I am using the following iptables script to redirect packets on port 443 to a proxy server:
iptables -t mangle -A PREROUTING -p tcp --dport 443 -j MARK --set-mark 2
I am redirecting it to my proxy server later on, which is working. For one host, however, I need to remove the iptables mark (i.e. the packets will not be redirected.) I tried the following:
iptables -t mangle -A PREROUTING -p tcp -s 192.168.0.47 --dport 443 -j ACCEPT
I have also tried (attempting to rewrite the mark to a different number):
iptables -t mangle -A PREROUTING -p tcp -s 192.168.0.47 --dport 443 -j MARK --set-mark 1
However none of them are working. Is there a --remove-mark? I couldn't find anything on Google.
Any help would be appreciated.
When using the MARK target, the mark is a added as a bitmask. If you check in the documentation, there's an optional [/mask] for the mark.
So use "--set-mark 0/2" to remove 2.
I figured it out. I used the following:
iptables -t mangle -A PREROUTING -p tcp ! -s 192.168.0.47 --dport 443 -j MARK --set-mark 2
To mark it so it doesn't mark the host in the first place.
I have a machine with 2 interfaces:
eth0 inet addr:1.1.1.1
eth1 inet addr:2.2.2.2
eth0 is a server, eth1 is the network on virtual machine.
I have ssh on server, so 1.1.1.1:22 is busy.
I need a rule for redirecting incoming connections on eth0 port 6000 to eth1, ip 2.2.2.100 on port 22 (virtual machine ip).
In this mode if I did, on an external machine,
ssh -p 6000 root#1.1.1.1
I would login on the virtual machine.
I tried this rule but it didn't work:
sudo iptables -P FORWARD ACCEPT
sudo iptables -t nat -A PREROUTING -p tcp -i eth0 --dport 6000 -j DNAT --to 2.2.2.100:22
Well there are like 1 million scripts/tutorials/things for this case, but if someone lands from google to here is something like this:
iptables -I FORWARD -d 2.2.2.2 -m comment --comment "Accept to forward ssh traffic" -m tcp -p tcp --dport 22 -j ACCEPT
iptables -I FORWARD -m comment --comment "Accept to forward ssh return traffic" -s 2.2.2.2 -m tcp -p tcp --sport 22 -j ACCEPT
iptables -t nat -I PREROUTING -m tcp -p tcp --dport 60000 -m comment --comment "redirect pkts to virtual machine" -j DNAT --to-destination 2.2.2.2:22
iptables -t nat -I POSTROUTING -m comment --comment "NAT the src ip" -d 2.2.2.2 -o eth1 -j MASQUERADE