iptables is the userspace command line program used to configure the Linux 2.4.x and 2.6.x IPv4 packet filtering ruleset. It is targeted towards system administrators. Please, when asking a question about iptables, add the output from the following command: iptables -L -v -n

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0
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14 views

vpnc router on CentOS not forwarding the rensponse

I'm mounting a vpnc router on an openstack environment. I mounted a CentOS Server with ip_forward enabled and iptables, with local IP 192.168.2.2. The remote network is 10.0.0.0/8 and the local ...
2
votes
3answers
1k views

How to disallow external access to 127.0.0.1? [closed]

I use tcp socket on 127.0.0.1:9000 to connect nginx to php5-cgi. However I want make sure that no extrnal request can be made to this IP, so that no attacker can obfuscate IP and bypass nginx to do ...
0
votes
0answers
18 views

ipt_CLUSTERIP: unknown protocol 1

I am trying to create a web cluster with two load balancers and a single public ip address The command I use is the following: iptables -I INPUT -d $CLUSTERIP -i $WAN_IF -j CLUSTERIP --new ...
6
votes
7answers
14k views

How do I list IP addresses blocked by iptables?

To prevent brute force attacks against ssh I've added some iptables rules (below). The question is: How can I list the blocked IP addresses? (1) iptables -A INPUT -i eth0 -p tcp --dport 22 -m state ...
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votes
0answers
24 views

Drop connections forward from Linux Firewall to Samba File Server

im working na Hotel and i have two different networks in same infrastructure. A) Administration network: 10.0.1.x / File Server 10.0.1.1 B) Customers network: 192.168.1.x On network B) i have a ...
1
vote
1answer
40 views

How to forward ports to DMZ using iptables and separate modem

I have a network that looks like this: ADSL VLAN 2 VLAN 3 ------[Modem]----------[firewall]----------[intranet PC] | | ...
1
vote
1answer
29 views

IP forwading amazon ec2 another server IP

I use this command in windows azure (NAT), to redirect all requests to another server with other IP iptables -t nat -A PREROUTING -i eth0 -d 10.240.154.15 -j DNAT --to-destination 192.188.47.63 ¿ ...
0
votes
1answer
24 views

Open port only on OpenVPN network with iptables

I'm running an OpenVPN network and one of the VPN clients in my network is a web server which provides access to some internal services used by my application. Normally, on a public facing web server ...
0
votes
2answers
47 views

How to remove this iptables rule?

happy new year !!! I have an iptables rule. When searching for it with sudo /sbin/iptables -L -n --line-numbers I am getting it Chain tcp_inbound (1 references) num target prot opt source ...
1
vote
2answers
839 views

iptables+iptables_netflow: iptables blocking netflow export?

I am running an iptables firewall on OpenSuSE 11.3 --recently I became interested in traffic monitoring and accounting, and to this end installed iptables_netflow module on the firewall and WANGuard ...
0
votes
1answer
26 views

redirecting iptables to privoxy does not work

I have set up a wireless access point on my Debian 8 laptop following this and this tutorial. When redirecting iptables to port 9040 it works but changing the port to 8118 which is the one privoxy ...
0
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0answers
25 views

Does netfilter reassemble IP fragments when packet is forwarded?

IP datagram should be reassemble in the termination of the path because the fragments may arrive from different paths. I think Netfilter need to reassemble a IP datagram to inspect the whole payload ...
0
votes
1answer
46 views

is iptables-save rule dump deterministic?

is the order of the parameters of iptables rule line deterministic in the iptables-save output? -A CHAIN1 -m mod1 -m mod2 -j CHAIN2 will be always the same, or I can expect it to be -A CHAIN1 -m mod2 ...
0
votes
1answer
25 views

I can't open any UDP port(inbound)

I am setting up a little IPTable. This is my current config: # Accept everything on the loopback interface iptables -A INPUT -i lo -j ACCEPT # Accept ICMP iptables -A INPUT -p icmp --icmp-type any ...
2
votes
2answers
93 views

ACCEPT statements in policy DROP

I'm trying to set up some rules using IPtables under Debian (Wheezy) and have been running in to some problems i think. The policy of INPUT is set to DROP. Does this drop everything based on the ...
-3
votes
3answers
7k views

Blocking WhatsApp and other IM traffic

In my office, I have set up a linux machine as router and provide internet connectivity to all clients. Behind this linux router I have set up a cisco wireless router, with which I have made internet ...
0
votes
0answers
29 views

nftables, bridge, lxc. Can't call into container

My first post so bear with me. I am using nftables to start to replace old ones. I am loving it, but obviously, my approach is a bit iptables-like and also highly procedural, rather than using the ...
0
votes
1answer
2k views

iptables forward rule not working in openwrt

I am trying to apply some iptables forwarding rules in openwrt. Here is my scenario - My server has two cards ath0 and br-lan. br-lan is connected to internet and ath0 to private network. The other ...
0
votes
0answers
24 views

Return traffic through same interface as entered

I've created a GRE tunnel on my Linux server (VPS, OpenVZ). Server gets a public IP address from this tunnel and I need it be accessible from Internet through it. There is already a default gateway, ...
0
votes
2answers
48 views

iptables: static ephemeral port maps

I have a VPN on my Linux server which does IPv4 NAT, example: iptables -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT iptables -A FORWARD -s 10.8.0.0/24 -j ACCEPT iptables -t nat -A ...
0
votes
2answers
36 views

is there a way from iptables/iproute to forward all traffic to my IDS and also keep the regular flow

The reason of this, is that to catch all packages into my IDS keeping my existing enviroment, so the IDS does not become a single point of failure. If route all my traffic into my IDS and from my IDS ...
1
vote
1answer
36 views

iptables only blocks OpenVPN on server startup

I'm currently in the process of setting up OpenVPN across multiple data centres on Linode. The OpenVPN set up is working great and I'm now focusing on getting my firewall set up so that my public and ...
0
votes
4answers
1k views

Server not reachable on all TCP ports from all locations

I have a very strange situation on a Linux (CentOS) server. Firstly, from my Ubuntu desktop PC, I can successfully connect to all services that are running on it, on ports 22, 80, 8080 and others. ...
0
votes
1answer
2k views

strongswan VPN on OpenWrt

Hi I'm running Barrier Breaker version of OpenWRT and I have setup a VPN according to: http://wiki.openwrt.org/inbox/strongswan.howto I can connect to the VPN with my iPhone or Mac (to 10.10.1.0/24 ...
0
votes
0answers
10 views

How can I proxy requests to a specific IP to a different IP on OS X?

On OS X how can I setup a route so that when I make a request to 10.0.0.1 it is redirected to localhost? Right now I can do curl localhost:3000 and get back a blob of HTML from my running node web ...
1
vote
2answers
237 views

How do I forward localhost traffic to a remote host with iptables?

I would like to set up my CentOS 6.5 box to forward connections to localhost (127.0.0.1) to the same port on a remote machine (e.g. 10.0.3.10). I've tried the iptables rule below, but when I attempt ...
6
votes
2answers
275 views

CentOS port forwarding not working

I'm using CentOS 6.5 and I added the following commands to my iptables to forward all incoming traffic on port 8088 to 4569: iptables -A PREROUTING -t nat -p udp --dport 8088 -i eth0 -j DNAT ...
0
votes
1answer
25 views

Connection lost to VPS While using iptables by default policy as DROP for INPUT, OUTPUT, FORWARD

I'am using iptables in many server's but now stuck with this issue while using default Policy as DROP. Here is my rules which i have used in VPS, Tried many time's everything seems fine but VPS ...
1
vote
3answers
1k views

How to block ALL communications with an IP-address using iptables?

I have a FreeBSD system behind a Linux-based router (using DD-WRT firmware). The FreeBSD system is running sshd and is regularly probed by various script-kiddies. It currently runs a script, that, ...
0
votes
1answer
1k views

apt-get update can not connect

i run a dedicated ubuntu 10.04 server. i use kvm/libvirt/virsh to run a virtual machine that's also ubuntu 10.04. i bridged the network (1 of 2 IPs is routed via NAT to the LAN, where my VM ...
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votes
2answers
49 views

how to force linux to accept packet with loopback ip

i have an embedded system with an Ethernet interface that needs to accept external packets with IP of 127.x.x.xx. is there a way to force Linux to accept external packets with this loop back address ...
1
vote
2answers
962 views

iptables 1.4 and passive FTP on custom port

after the upgrade from debian squeeze to wheezy I've got a problem with passive FTP connection. I could narrow it to be iptables related, as I could connect via FTP w/o problems after adding my IP to ...
-2
votes
0answers
44 views

Solution for transparent proxy

I'm looking for a tool, that will forward all requests to parent proxy. In my case all traffic with destination port 80 - is redirected to a local instance of proxy-server, that forwards it to some ...
2
votes
1answer
85 views

UDP Traffic from outside to docker container is dropped after container restart

following situation: i have a hardware box with Ubuntu 14.04LTS as host for docker 1.4 I'm running an ELK stack in several containers. Curenntly the logstash container is exposing only port 514 to ...
0
votes
0answers
19 views

Why iptables state setting changes from 1.3.x to 1.4.x?

I intend to set iptables rules in the purpose of allowing to access outer website from current machine, but not allow any positive connection to this machine. Thus, my iptables is set as follows: ...
1
vote
2answers
928 views

Sendmail Domain of sender address does not resolve. Unable to send any emails.

I've got myself in a muddle with Sendmail. I've newly inherited responsibility for an app that uses sendmail and I have no previous experience. I'm using Ubuntu Ubuntu 10.04.4 LTS. Recently we ...
4
votes
3answers
6k views

Centos 7 save iptables settings

Problem: iptables resets to default settings after server reboot. I'm trying to set rule like this: iptables -I INPUT -p tcp --dport 3000 -j ACCEPT after that I do: service iptables save and it ...
1
vote
1answer
74 views

How do iptables policies work?

I've added some basic rules: iptables -A INPUT -p tcp --dport 22 -j ACCEPT iptables -A INPUT -p tcp --dport 80 -j ACCEPT Then, command to close all other ports with: iptables -A INPUT -j DROP ...
2
votes
2answers
52 views

What is the difference between iptables -X and iptables -F?

In many examples, I see the following 2 consecutive commands: iptables -F iptables -X From the man page, I cannot figure out the difference between flushing and deleting. Is there a difference ...
0
votes
0answers
18 views

iptables treating vpn traffic to public IP differently [duplicate]

I have a VPN that is intended to provide access to the internals of an iptables defined cluster. The firewall on each machine has a list of rules a la -A INPUT --src <machine0_ip> -j ACCEPT -A ...
0
votes
1answer
48 views

iptables fails to load nf_conntrack_ftp [duplicate]

I have recently had to rebuild my iptables configuration and when I run service iptables restart I now receive the following error line: iptables: Loading additional modules: nf_conntrack_ftp ...
2
votes
3answers
22 views

Use iptables to log connections except for two addresses

We would like to use iptables to log all network connections except if the connecting address is A.B.C.D or the connecting address is E.F.G.H. These two addresses cannot be combined into a single CIDR ...
0
votes
1answer
23 views

Measuring request response time by port

So, I'm currently working on a project in which I spin up a set docker image on a number of different machines and configurations. This image basically contains a web server that accepts a number of ...
0
votes
2answers
875 views

/etc/init.d/iptables-persistent start returns fail but seems to work

I am trying to activate iptables-persistent on an Ubunutu server. Config files are located in /etc/iptables/rules.v4 /etc/iptables/rules.v6 I have installed the iptables-persistent package. ...
0
votes
0answers
5 views

Port Forward to Localhost (DD-WRT) [migrated]

I have configured an SSH tunnel on my DD-WRT router using the default port 22. I would like to open another port on my router as a proxy port for SSH, say port 80, in case a firewall prevents me from ...
0
votes
1answer
67 views

Connection was reset - Apache

I have a server in which I can ssh using the live IP. The server is connected through a DMZ port. whenever I try to access the web server in the server I get Connection was reset. My SeLinux is ...
1
vote
2answers
199 views

Forward one IP to a docker container

As far as I understood, docker run containers with their own IPs, and fully open ports, on the bridge interface docker0. Let's say I launch a container, and it has its own IP: 172.17.0.11, and I have ...
0
votes
1answer
31 views

pptp gateway with ssh access

I am desperately trying to setup a gateway-server that forwards all local traffic to a ppp0 connection but is still reachable via ssh on the local network. The point-to-point connection establishes ...
2
votes
4answers
926 views

Using IPTables to forward local requests on one port to a remote server on another port

I have an application in a Docker container. I have the DB in another Docker container. The DB container has an exposed port of 49155. The application requires that the database be exposed on port ...
2
votes
3answers
2k views

How can I achieve OpenVPN client routing without NAT on Linode

I've set up an OpenVPN network, and it is working properly in the sense that I can access the inner/LAN machines from the remote client. However, my problem is that all traffic from the remote ...