Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
This question does not appear to be about a specific programming problem, a software algorithm, or software tools primarily used by programmers. If you believe the question would be on-topic on another Stack Exchange site, you can leave a comment to explain where the question may be able to be answered.
Closed 8 years ago.
Improve this question
I have set up several iptables rules , and at the end I set The Policies to Drop
But It will Drop every thing even my rules
iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT
iptables -A INPUT -p tcp -s 127.0.0.1 --dport 3306 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -p tcp -d 127.0.0.1 --dport 3306 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A INPUT -p tcp -s x.x.x.x --dport 3306 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -s 127.0.0.1 -p tcp -m state --state NEW,ESTABLISHED -m multiport --sports 110,25,143 -j ACCEPT
iptables -A INPUT -p tcp -s x.x.x.x --dport 3690 -j ACCEPT
iptables -A OUTPUT -p tcp -s 127.0.0.1 --sport 3690 -j ACCEPT
iptables -A INPUT -p tcp -s 0/0 --sport 80 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A INPUT -p tcp -s x.x.x.x --sport 22 --dport 22 -j ACCEPT
iptables -P INPUT DROP
iptables -P OUTPUT DROP
iptables -P FORWARD DROP
but I cant access my website or ssh . Please help, thanks in advance
Iptables -nvL :
Chain INPUT (policy ACCEPT 3158 packets, 285K bytes)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT tcp -- * * 127.0.0.1 0.0.0.0/0
tcp dpt:3306 state NEW,ESTABLISHED
0 0 ACCEPT tcp -- * * 82.115.26.145 0.0.0.0/0 tcp dpt:3306 state NEW,ESTABLISHED
0 0 ACCEPT tcp -- * * 82.115.26.145 0.0.0.0/0 tcp dpt:3690
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp spt:80 state NEW,ESTABLISHED
0 0 ACCEPT tcp -- * * 82.115.26.145 0.0.0.0/0 tcp spt:22 dpt:22
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
Chain OUTPUT (policy ACCEPT 1152 packets, 160K bytes)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all -- * lo 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT tcp -- * * 0.0.0.0/0 127.0.0.1 tcp dpt:3306 state NEW,ESTABLISHED
0 0 ACCEPT tcp -- * * 127.0.0.1 0.0.0.0/0 state NEW,ESTABLISHED multiport sports 110,25,143
0 0 ACCEPT tcp -- * * 127.0.0.1 0.0.0.0/0 tcp spt:3690
but assume the policy is DROP for all chains
You have the fundamentals there but they are a little mixed up. INPUT needs a source ip and destination port and OUTPUT needs a destination ip and source port. Traffic coming in will be NEW or ESTABLISHED and traffic going out from server services (in a client/server design) will be ESTABLISHED.
iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT
iptables -A INPUT -p tcp -s x.x.x.x --dport 3306 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -p tcp -d x.x.x.x --sport 3306 -m state --state ESTABLISHED -j ACCEPT
iptables -A INPUT -p tcp -s x.x.x.x --dport 3690 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -p tcp -d x.x.x.x --sport 3690 -m state --state ESTABLISHED -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -p tcp --sport 80 -m state --state ESTABLISHED -j ACCEPT
iptables -A INPUT -p tcp -s x.x.x.x --dport 22 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -p tcp -d x.x.x.x --sport 22 -m state --state ESTABLISHED -j ACCEPT
iptables -P INPUT DROP
iptables -P OUTPUT DROP
iptables -P FORWARD DROP
Related
We need to find port on a server and read info from this port. If we will try to use nmap here - we will be banned. Because iptables config, that blocks scans. What nmap flags can we use for finding this port and not be banned?
first port iptables:
ipset create scanned_ports hash:ip,port family inet hashsize 32768 maxelem 65536 timeout 1
iptables -A INPUT -p tcp -m state --state INVALID -j DROP
iptables -A INPUT -p tcp -m state --state NEW -m set ! --match-set scanned_ports src,dst -m hashlimit --hashlimit-above 1000/hour --hashlimit-burst 1000 --hashlimit-mode srcip --hashlimit-name portscan --hashlimit-htable-expire 10000 -j SET --add-set port_scanners src --exist
iptables -A INPUT -p tcp -m state --state NEW -m set --match-set port_scanners src -j DROP
iptables -A INPUT -p tcp -m state --state NEW -j SET --add-set scanned_ports src,dst
nohup python -mSimpleHTTPServer $_PORT > /dev/null &
second port iptables:
ipset create scanned_ports hash:ip,port family inet hashsize 32768 maxelem 65536 timeout 1
iptables -A INPUT -p tcp -m state --state INVALID -j DROP
iptables -A INPUT -p tcp -m state --state NEW -m set ! --match-set scanned_ports src,dst -m hashlimit --hashlimit-above 1000/hour --hashlimit-burst 1000 --hashlimit-mode srcip --hashlimit-name portscan --hashlimit-htable-expire 10000 -j SET --add-set port_scanners src --exist
iptables -A INPUT -p tcp -m state --state NEW -m set --match-set port_scanners src -j DROP
iptables -A INPUT -p tcp -m state --state NEW -j SET --add-set scanned_ports src,dst
iptables -I INPUT -p tcp --tcp-flags ALL SYN -j REJECT --reject-with tcp-reset --dport $_PORT
nohup python -mSimpleHTTPServer $_PORT > /dev/null &
I have configured a website but it seems not to be accessible and I found that I must open a port of 5250. I searched and I could not find a good way to do it. I am wondering if anyone could advise ?
I was reading that by default it is stored in
vi /etc/sysconfig/iptables
which I only see
# sample configuration for iptables service
# you can edit this manually or use system-config-firewall
# please do not ask us to add additional ports/services to this default configuration
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 22 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 80 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 8089 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 443 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
then I added the following
-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 5250 -j ACCEPT
then I restarted
I also tried to see the firewall status which made me more confused
# systemctl status firewalld
● firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
Active: inactive (dead)
Docs: man:firewalld(1)
I am trying to limit HTTP requests to maximum 20 requests/second if more than that reject but i want to exclusion requests to (.png,.js,.css) files from this rule, I used the following code
iptables -N RATELIMITING
iptables -I INPUT -p tcp --dport 80 -m string --algo bm --string "/" -j RATELIMITING
iptables -A RATELIMITING -p tcp --dport 80 -m string --algo bm --string "\.(jpe?g|png|gif|js|css|woff)$" -j RETURN
iptables -A RATELIMITING -p tcp --dport 80 -m state --state NEW -m recent --set
iptables -A RATELIMITING -p tcp --dport 80 -m state --state NEW -m recent --update --seconds 1 --hitcount 20 -j REJECT --reject-with tcp-reset
iptables -A RATELIMITING -j RETURN
it does block requests more than 20 requests but it doesn't exclusion (.png,.js,.css) files from rule,if I send 20 requests to those files you also get blocked, what am I doing wrong here?
I have two network interface, eth0 is the internal network necessary for the connection of PCs with the softphone and eth1 to link to internet. I'm using iptables on CentOS 6.5 to direct all the outputs of the Freepbx (Asterisk) to eth1, but I don't have success.
The rule
iptables -A PREROUTING -i eth1 -t mangle -p tcp --dport 5060 -j MARK --set-mark 1
Take a ook at sip.conf. In the [general] section, there is a bindaddress or udpbindaddress. Set it to 0.0.0.0 to make sure asterisk listens on all interfaces. You can check it by:
netstat -lnap | grep 5060
udp 0 0 0.0.0.0:5060 0.0.0.0:* 30822/asterisk
Then restrict access to unnecessary interfaces using iptables, like (note the order):
iptables -A INPUT -i eth1 -p udp --dport 5060 -j ACCEPT
iptables -A INPUT -p udp --dport 5060 -j DROP
iptables -A OUTPUT -o eth1 -p udp --sport 5060 -j ACCEPT
iptables -A OUTPUT -p udp --sport 5060 -j DROP
If public ip on same server, you need use INPUT table and ACCEPT destination.
If it on other host, you have use DNAT.
nginx-proxy is a Docker container that acts as a reverse proxy to other containers. It uses the Docker API to detect other containers and automatically proxies traffic to them.
I have a simple nginx-proxy setup: (where subdomain.example.com is replaced with my domain)
docker run -d -p 80:80 -v /var/run/docker.sock:/tmp/docker.sock:ro jwilder/nginx-proxy
docker run -e VIRTUAL_HOST=subdomain.example.com kdelfour/cloud9-docker
It works with no problem when I have my firewall off. When I have my firewall on, I get a 504 Gateway Time-out error from nginx. This means that I'm able to see nginx on port 80, but my firewall rules seem to be restricting container-to-container and/or Docker API traffic.
I created a GitHub issue, but the creator of nginx-proxy said he had never run into this issue.
These are the "firewall off" rules: (these work)
iptables -F
iptables -P INPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -P OUTPUT ACCEPT
These are my "firewall on" rules: (these don't work)
# Based on tutorial from http://www.thegeekstuff.com/scripts/iptables-rules / http://www.thegeekstuff.com/2011/06/iptables-rules-examples/
# Delete existing rules
iptables -F
# Set default chain policies
iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT DROP
# Allow loopback access
iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT
# Allow inbound/outbound SSH
iptables -A INPUT -i eth0 -p tcp --dport 22 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -o eth0 -p tcp --sport 22 -m state --state ESTABLISHED -j ACCEPT
iptables -A OUTPUT -o eth0 -p tcp --dport 22 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A INPUT -i eth0 -p tcp --sport 22 -m state --state ESTABLISHED -j ACCEPT
# Allow inbound/outbound HTTP
iptables -A INPUT -i eth0 -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -o eth0 -p tcp --sport 80 -m state --state ESTABLISHED -j ACCEPT
iptables -A OUTPUT -o eth0 -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A INPUT -i eth0 -p tcp --sport 80 -m state --state ESTABLISHED -j ACCEPT
# Allow inbound/outbound HTTPS
iptables -A INPUT -i eth0 -p tcp --dport 443 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -o eth0 -p tcp --sport 443 -m state --state ESTABLISHED -j ACCEPT
iptables -A OUTPUT -o eth0 -p tcp --dport 443 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A INPUT -i eth0 -p tcp --sport 443 -m state --state ESTABLISHED -j ACCEPT
# Ping from inside to outside
iptables -A OUTPUT -p icmp --icmp-type echo-request -j ACCEPT
iptables -A INPUT -p icmp --icmp-type echo-reply -j ACCEPT
# Ping from outside to inside
iptables -A INPUT -p icmp --icmp-type echo-request -j ACCEPT
iptables -A OUTPUT -p icmp --icmp-type echo-reply -j ACCEPT
# Allow outbound DNS
iptables -A OUTPUT -p udp -o eth0 --dport 53 -j ACCEPT
iptables -A INPUT -p udp -i eth0 --sport 53 -j ACCEPT
# Allow outbound NTP
iptables -A OUTPUT -p udp -o eth0 --dport 123 -j ACCEPT
iptables -A INPUT -p udp -i eth0 --sport 123 -j ACCEPT
# This bit is from https://blog.andyet.com/2014/09/11/docker-host-iptables-forwarding
# Docker Rules: Forward chain between docker0 and eth0.
iptables -A FORWARD -i docker0 -o eth0 -j ACCEPT
iptables -A FORWARD -i eth0 -o docker0 -j ACCEPT
ip6tables -A FORWARD -i docker0 -o eth0 -j ACCEPT
ip6tables -A FORWARD -i eth0 -o docker0 -j ACCEPT
iptables-save > /etc/network/iptables.rules
Why won't the proxy work when I have my firewall on?
Thanks to advice by Joel C (see the comments above), there was a problem on the FORWARD chain which I fixed like so:
iptables -A FORWARD -i docker0 -j ACCEPT