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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2answers
43 views

How to forward traffic to different nics based on source?

I'm a newbie to IPtables, but am looking to do send traffic to a specific card based on the source. Here's what I would like: eth0 - all traffic comes in on this NIC Depending on the source IP, I ...
-1
votes
1answer
60 views

Very weird port forward on Ubuntu

I have a droplet running Ubuntu 13 on Digital Ocean. On it I have a node server running on port 5000. From the outside I can access that server on port 80, but I don't know what's forwarding the ...
1
vote
1answer
20 views

Forward traffic to port 80 on WHM via iptables

I'm working on a VPS (DV) that's hosted on Media Temple. I need to forward traffic from port 8774 to 80. I logged in as root, ran iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 8774 -j ...
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votes
2answers
57 views

Iptables with dynamic ip list

We have 5 servers in EU datacenter and 5 servers in US datacenter. All servers have some Redis instances installed and Redis port is opened for IP adresses from list (via iptables). All Redis's ...
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votes
1answer
22 views

Postgres Remote Connection Timeout

I've been reading tutorials extensively to help figure out my problem, but to no avail. I have a Redhat VM that I've installed Postgres on that I'm trying to make available for remote connections. ...
0
votes
1answer
27 views

Iptables SMTP re-routing on a proxy

I'm lost... Any help would be appreciated :) I have a mailserver. Unfortunately, the provider deny the smtp 25. I don't want to use ESMTP or a vpn. So here is the project : I have a dedicated server ...
-1
votes
1answer
48 views

Forward incoming packets from port 25565 to natted internal client? IPTables [closed]

I have been learning to use iptables recently and i made a small nat network in virtualbox. I have a Debian server Natting for the internal clients. One of the internal clients is hosting a minecraft ...
0
votes
2answers
82 views

bridging LXC containers to host network with different IP range

I'm pretty new to linux, and I have been struggling with a problem for the past week or so... I am trying to setup a cluster of LXC containers on a workstation (host) which is has IP 192.168.10.33 ...
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0answers
45 views

Ubuntu IPTables DROP/REJECT Rule Disappearing?

I am attempting to use iptables to manage the firewall on a Ubuntu 14.04.1 LTS. I want to restrict all HTTP/HTTPS traffic to our network (XXX.XXX.0.0/16) and all UDP/MySQL activity to localhost. The ...
1
vote
1answer
49 views

OpenVPN Hairpin Nat

I have an OpenVPN set up that looks like this: +------------------------------------------------------+ | ...
1
vote
0answers
36 views

Dovecot/Postfix mail server replies to [SYN] with [RST, ACK] when user attempts to connect (POP3). Likely iptables?

Currently I am trying to trouble shoot an e-mail server that will allow users to send e-mail, but not log in to the server (POP3) or receive e-mail using their Outlook clients. Previously this was ...
0
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0answers
58 views

Ubuntu as IPSec L2TP client with NAT traversal

Goog afternoon, I have a corporate local network located behind NAT. There is another NAT in this local network for the corprorate server on Ubunit 12.04. So if clients connect to that server ...
0
votes
1answer
113 views

SSH On Another Port Debian 7.7

I cannot seem to SSH into my server on another Port. I have an identical setup on another server, but I am baffled now if my issue is with IPTables or something else. Does anyone see what I am doing ...
0
votes
0answers
94 views

Force all traffic from one user through an OpenVPN tunnel on Debian 6 with iptables and ip route

I’m trying to force all traffic of one user through an OpenVPN tunnel. It is giving me grey hairs. The current situation is that I can either allow all traffic for this particular user, and it will go ...
2
votes
1answer
213 views

How can redirect requests to my external IP address/port to a different external IP address/port in Linux without changing the source IP address?

I can use the following commands, but they change the source IP address: iptables -t nat -A PREROUTING -p tcp --dport port -j DNAT --to-destination dest_ip:port iptables -t nat -A POSTROUTING -j ...
0
votes
0answers
104 views

Only allow SSH from specific IP to evade VPN connection?

I want a Linux server to use the VPN connection for all traffic that is not SSH from a specific IP. If the VPN connection becomes unavailable, not other communication than SSH with the specific IP ...
0
votes
2answers
80 views

IPTables only solution to block any IP address who has made too many connections or reconnections

I’m looking for an IPTables only solution to block any IP address who has made too many (e.g. more than 5) connections or reconnections within a short period of time (e.g. 1 minutes) on a certain ...
1
vote
1answer
40 views

Debian port(s) not responding

I am fairly new to servers. I am trying to run a shoutcast server on debian. Shoutcast runs on a default port of 8000. My problem is it will not load when visiting xxx.xxx.xx.xxx:8000. When I log in ...
0
votes
1answer
39 views

Running snort behind iptables

I run a Centos 6.5 server with a highly restrictive iptables ruleset allowing incoming traffic only on a small handful of tcp ports (8 in total) and blocks all incoming unsolicited UDP traffic. I ...
1
vote
1answer
209 views

How to ban Syn Flood Attacks using Fail2Ban?

In my log, I am frequently seeing dropped ips like this: > Oct 30 17:32:24 IPTables Dropped: IN=eth0 OUT= > MAC=04:01:2b:bd:b0:01:4c:96:14:ff:df:f0:08:00 SRC=62.210.94.116 > ...
3
votes
1answer
295 views

Does closed Port 25 cause mail to be marked as spam?

I have a web server where I have installed Postfix for sending emails only. All incoming mails will be handled by google apps and not my web server. Using iptables rules, I have blocked all incoming ...
0
votes
0answers
54 views

SFTP Reverse-Proxy using iptables on custom port

I want to give SFTP access to anyone into to my Server (IP: ss.ss.ss.ss) passing through Proxy (reverse-Proxy? IP: pp.pp.pp.pp), so that IP ss.ss.ss.ss is never seen by whoever is connecting to the ...
0
votes
2answers
49 views

Can't block spammy IP

I'm being attacked by 37.59.4.76. It's sending me a great amount of data, which is destroying my dataplan. I've added the iptables Chain num pkts bytes target prot opt in out ...
1
vote
1answer
46 views

iptables destination NAT from one range to another

I am trying to make destination NAT from one range (192.168.2.0/24) to corresponding ip addresses in another range (192.168.1.0/24). I have managed to do this ip by ip iptables -t nat -A PREROUTING ...
1
vote
0answers
95 views

Forward single port between subnets on dd-wrt router

I have a DD-WRT router with two subnets, 192.168.0.0/24 and 192.168.8.0/24. The latter is used for a 'guest' WiFi network. Traffic between subnets is filtered using iptables. What I would like to ...
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votes
0answers
47 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 ...
0
votes
1answer
209 views

Fail2ban MTA=Postfix Setting in Jail Config giving Error

In /etc/fail2ban/jail.local, when I have the MTA setting to Postfix, Fail2Ban is showing an error and is unable to start. [DEFAULT] ignoreip = 127.0.0.1/8 bantime = 1800 ...
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votes
0answers
39 views

What does Nginx Proxy Filter in Fail2ban really do?

What does Nginx Proxy Filter in Fail2ban really do? I am currently setting up Fail2Ban for Nginx. Almost everywhere I've read, they all have included a setting for [nginx-proxy] proxy filter. From ...
1
vote
1answer
78 views

Fail2ban jail.local vs jail.conf

Does jail.local file act as an override to jail.conf or as a replacement to jail.conf? When I was learning about Fail2Ban from tutorials, most of them usually say either to copy jail.conf to ...
0
votes
2answers
50 views

Controlling the depth of iptables RETURN (or how to skip chains)

I have the following setup for iptables INPUT ParentChain ChildChain1 ChildChain2 ... More Rules on INPUT .... How can I return from ChildChain1 back to INPUT just after ...
0
votes
1answer
51 views

fail2ban flushing my existing IPTABLES rules

I just implemented fail2ban on a server for testing purposes. I have a BLACKLIST chain which blocks a huge set of CIDR masks that I don't want to reach my server. When fail2ban is triggered by a ...
0
votes
1answer
50 views

Fail2ban not working on Ubuntu 12.04

I'm trying to implement fail2ban on a Ubuntu 12.04 x64 server. I've done the following: apt-get install fail2ban Made a copy of jail.conf in /etc/fail2ban/jail.conf.local here's an excerpt: ...
0
votes
2answers
196 views

When the OpenVPN client is on, remote ssh access don't works [closed]

I'm a new user forum and I'm doing my first VPN setup. I have purchased a VPN service with PrivateInternetAccess. I'm setting up a Linux VM (CentOS 6.5 server) on a VMware ESXi remote host. It's ...
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votes
1answer
35 views

Rewrite source with iptables [closed]

I'm going to route a static IP from a VPS to my OpenWRT router. They are connected with OpenVPN - the server is the 10.8.0.1 and the router the 10.8.0.6. My public IP is 1.1.1.1 for example, and all ...
0
votes
0answers
81 views

iptables - dropping specific established connections after X hours

Is there a way with iptables to drop specific established connections after X hours? We have an application with limited connection support, and occasionally we see some tcp sessions that shouldn't ...
2
votes
2answers
70 views

Running own DNS in intranet, how to reach outside DNS from clients

The Scenario: I am creating a Network for 8 Windows 7 Workstations running in a Student Laboratory. They are supposed to browse the internet, but not to be reached from outside their intranet. To ...
1
vote
1answer
60 views

MySQL on LAN not working when IPTables enabled

I have two Centos VM. The IP Addresses are as follows : VM_1 => 10.99.0.10 VM_2 => 10.99.0.12 Apache and PHP are in VM_1 and MySQL is in VM_2. Both are having iptables rules. VM_2 is working ...
1
vote
2answers
46 views

Is it safe to move “ACCEPT state RELATED,ESTABLISHED” to the top?

I've the following iptables configuration: Chain INPUT (policy DROP 11 packets, 604 bytes) num pkts bytes target prot opt in out source destination 1 127 11093 ...
-1
votes
1answer
40 views

Linux - Disable routing but allow bridging

I have a Linux server that is running the KVM hypervisor. I have multiple bridges on this server (that are on different VLANS). Is there an "easy" way to make sure that bridge hoping (i.e. routing ...
0
votes
1answer
64 views

Setting up iptables for port forwarding of incoming requests over a OpenVPN Client on a Router

I have a Router that runs DD-WRT and a OpenVPN Client that connects and redirects every request over the VPN. My VPN provider supports port forwards, the problem is my router does not forward ...
0
votes
0answers
23 views

HowTo: Let ufw block single IPs when default policy is ALLOW

I want to be able to block certain IPs from accessing my server. As I don't really know what services are running on what port on the machine, I decided to quick&dirty let ufw's default policy be ...
0
votes
1answer
64 views

how to run pptp over redsocks proxy

I have one (virtual) Linux box in Ubuntu, that has redsocks set up done. Inside the machine, I could confirm that the the redsocks did work (use wget to check the external IP). Now, I want other ...
0
votes
1answer
49 views

iptables not allowing ssh

This is my iptable configuration. But I cannot connect with ssh with these rules. What am I doing wrong? I want to block all traffic except ssh coming from x.x.x.x ip address. iptables -F iptables -X ...
0
votes
1answer
28 views

DNAT packet after decryption of ipsec

how to DNAT packet decrypted by ipsec. encrypted packet is: sourceIP: 192.168.4.6 destIP 10.10.0.100: If i simply : iptables -t nat -A PREROUTING d 10.10.0.100 -j DNAT --to-destination 10.0.0.5 ...
0
votes
0answers
9 views

centos 6, vsftpd,user access

Is there a way to block users access to particular server interface? I have a server with three interfaces, eth0, eth1, eth2, and would like to block access to eth0 for particular user. For example ...
-1
votes
1answer
111 views

How to determine what traffic is being dropped / blocked base on iptables log

I have followed the example for iptable logging from https://help.ubuntu.com/community/IptablesHowTo#More_detailed_Logging sudo iptables -I INPUT 5 -m limit --limit 5/min -j LOG --log-prefix ...
0
votes
0answers
72 views

Why is the first of two post-up commands for routing in interfaces configuration not automatically processed

We managed to connect our servers to two distinct networks and everything works fine. We use routing rules that ensure that server responds to the right network. I followed the instructions under ...
1
vote
0answers
41 views

NAT for IPSEC access?

Please help to understand if the following configuration can be created. I have IPSEC connection with my customer. It is site2site vpn between customer network and my network 10.102.103.0/28. This ...
0
votes
0answers
48 views

How can I log and maybe even block IPs that send lots of incoming UDP traffic?

we run a voice / teamspeak server which receives legitmate traffic on port 9987 from many ips. Sometimes we get DDoSed. So people use single Servers and send 1-3 Gbits of UDP Floods to that port. This ...
0
votes
1answer
39 views

open all traffic on the pptp interface iptables [closed]

I set up a PPTP client in Ubuntu. Filter iptables denies network access to everything except TOR and PPTP client. *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT DROP [0:0] -A OUTPUT -d ...