0
votes
1answer
11 views

Logging packets with iptables

I am not all that experienced with iptables, but I am trying to log dropped packets. From what I have read log messages created with iptables are supposed to be written to /var/log/kern.log. My issue ...
0
votes
0answers
11 views

IP rule table look up does not seem to work

I have a sytem with three network interfaces. Below is the configuration that I'm trying to set up. wlan0 (its actually an WiFi AP interface) - other devices connects via this interface. net1 - ...
0
votes
0answers
23 views

Meaning of Bridge-Check in iptables flowchart

In the famous iptables flow-chart what does bridge-check exactly stands for ? I couldn't find any documentation. The only clue I found was while scanning the MikroTik RouterOS documentation ( ...
1
vote
1answer
34 views

Most secure way to have IPtables auto-loaded using Debian / Linux

I'd like to know the safest way to load iptables using Debian. Of course, I can use a script that uses iptables-restore : #!/bin/sh iptables-restore < /etc/firewall.conf but : 1) where is the ...
2
votes
1answer
13 views

How to apply ipfw rules to domains that resolves to multiple IPs?

Suppose I wanted to use ipfw to throttle uploads to youtube. The uploads are made to upload.youtube.com but this domain resolves into multiple different IPs (which also appear to change over time). ...
-1
votes
1answer
18 views

Route traffic to a destination to another destination using iptables

How to route traffic to a destination to another destination and receive response using iptables I have two vps on cloud. Lets say VPS-A and VPS-B. If a request to 8.8.8.8 generated from VPN-A, I ...
0
votes
0answers
10 views

Forward traffic from specific ip addresses to another port iptables

I can't figure out the syntax to forward TCP traffic from specific ip addresses to another port using ip tables. Lets say I want any TCP traffic from 1.2.3.4 to port 80 to be forwarded to port 81. ...
1
vote
0answers
12 views

Site to Site VPN - Openswan and CISCO A2A

Below is the diagram that the VPN connection between Openswan server and CISCO A2A. client A and B are remote hosts with static ips. client X and Y are behind the Cisco firewall. I can see ...
0
votes
0answers
9 views

Block all outgoing ports from iptables.

I have a windows xp machine running specific application which can be access by single port (27500). there is nothing else i want to access on this machine. If i block all outgoing ports from this ...
0
votes
1answer
21 views

iptables does not seem to be applying SNAT to packets sent on a raw socket

I'm writing packets from a user space program to my wireless interface wlan0. I've set up a SNAT rule with iptables as follows iptables -t nat -A POSTROUTING -o wlan0 -j SNAT --to 192.168.1.3 And ...
1
vote
1answer
15 views

Open ports in Ubuntu 13.10 server

Im setting up a realtime gameserver fps-game, and then i need to configure ports. Just to mention, i will setup multiple servers for this game on the same ip address, which means i must open multiple ...
0
votes
0answers
13 views

How to IP redirect all requests to public ip back to router

Using OpenWrt Backfire 10.03.1 on Linksys WRT54GL. Till today my ISP's modem used to loopback all traffic with self-destination IP back to itself. (for example if my WAN IP is 8.8.8.8 and I perform ...
1
vote
1answer
57 views

OpenWRT Firewarll INPUT Chain allowing everything?

I haven't done anything to my the default firewall rules except open a port for ssh from the wan and add the rules for OpenVPN as defined in this tutorial: ...
0
votes
0answers
47 views

Intermittent disconnections when using OpenVPN over SSH tunnel; possible iptables issue?

I've recently set up a Debian Wheezy server with OpenVPN to help out some friends in areas where internet censorship is a problem (including the blocking of VPN traffic in general). To overcome this, ...
0
votes
1answer
28 views

Port Forwarding with the real IP-address

How to implement port forwarding, so that would be displayed on the host real IP and non-IP machine, as it comes with SNAT DNET with IPTABLES The scheme is about the The machine-HETE with IP ...
0
votes
1answer
236 views

CentOS 7.x iptables

I have manually edited the /etc/sysconfig/iptables file in my CentOs 7.x installation , I have two entries and two processes running at the respective ports. I am able to telnet/access port 2181 but ...
0
votes
0answers
24 views

Why won't my proxy server connect to the internet?

I'm setting up a dedicated machine to run a transparent proxy server for my network, but for unknown reasons, clients can connect to the machine, but the internet isn't working. There seems to be a ...
0
votes
1answer
80 views

squid proxy slow response

We are using the squid proxy in our setup and implemented as transparent proxy with user authentication. Before couple of days, while we are trying to setup the iptables the squid started performing ...
0
votes
0answers
33 views

How to correctly configure iptables on a laptop?

I have run these commands (tried switching the order too) because I want to set up a firewall on my laptop so that nobody can connect to it (except of course in response to a connection I've made): ...
0
votes
0answers
125 views

udp client sending ICMP “port unreachable” when receiveing messages from the server

(Note: I moved this question from StackOverflow, because it's to be considered off-topic there, better fits here, and still unsolved) I have a udp client using luasocket, basically doing this (with a ...
1
vote
1answer
35 views

Should my server ever need to directly communicate with the NAT gateway?

What I mean by ``directly communicate'' Does it ever need to receive packets with the gateway's IP address as the source IP address, or send packets with the gateway's IP address as the destination ...
0
votes
0answers
9 views

Redirect external request thru VPN

I'm using Centos 5.4 and I'm trying to use the XMPP outside the company. But, the XMPP only works with the VPN. VPN connects and the XMPP become 10.0.2.49:5222 I tried to use iptables using this: ...
0
votes
1answer
35 views

Redirect ports with iptables

I need to do redirect port 443 on all interfaces to 8080 on one interface using iptables on a box with 2 NICs. I also need to block pretty much anything else on those interfaces. Here is my iptables ...
0
votes
1answer
50 views

block network access to a domain (ubuntu)

I have a few ubuntu servers in various geographies. I want to block all outgoing connections from all ubuntu machines (all processes) to several domains, e.g. www.server.com. I know iptables can block ...
0
votes
3answers
35 views

outgoing ssh fails from only one machine on lan to outside network

I have multiple servers in my LAN (which I'll refer to as Box1), and they are all able to make outgoing SSH connections, except one that stopped recently, which I'll refer to as Box2 (actually, I'm ...
0
votes
2answers
55 views

Wifi sharing over eth0

There are a lot of tutorials how to share network connection with your usb wifi adapter and I tried lots of them but it is still not working. Can you please help me with my problem. Here is my network ...
0
votes
1answer
28 views

Cant connect to eth0 after wlan0 sharing with iptables

I wanted my Ubuntu server to act as a wifi hotspot. So I set up hostapd to allow wifi connections. I then setup dnsmasq to provide the DHCP settings. I then added the following iptables rules, so ...
1
vote
5answers
90 views

How to forward traffic using iptables rules?

I am new to iptables and I have been doing Google searches for a few days now without finding a good solution to this problem. I have computer A with a public ip address (say 192.0.2.1) that can ...
0
votes
1answer
90 views

Asterisk server firewall script allows 2-way audio from incoming calls, but not on outgoing?

I'm running an Asterisk PBX on a virtual machine directly connected to the Internet and I really want to prevent script kiddies, l33t h4x0rz and actual hackers access to my server. The basic way I ...
1
vote
1answer
33 views

Add IPtables rule by script at the request of another computer

I wonder, is it possible to make an script, which adds rule in iptables by request from other pc? I mean, script "knows" what to do, but addres for rule comes from request. And how do you think it ...
0
votes
1answer
130 views

Block All Traffic and Allow from Defined IP only in IPTABLES

I want to create a gateway firewall for my network . I want to block all the internal traffic on gateway and allow it from two computers only . On gateway --> eth0 is network card in gateway PC ...
1
vote
1answer
116 views

Combination of NAT, DHCP, and OpenVPN on lubuntu 14.04

Okay, so I've got a set up, where eth0 my internal IP address (192.168.1.3) it has been configured as my default gateway using the iptables this sudo sysctl -w net.ipv4.ip_forward=1 sudo ...
0
votes
1answer
52 views

IPTables and PPTPd

I'm trying to add the line -A POSTROUTING -i ppp0 -j MASQUERADE to my IPTables in order to allow VPN to have access to the entire internal and external network (eth0, and eth1), but when I try to ...
0
votes
1answer
85 views

iptables --append FORWARD required for routing between NIC alias IPs?

I have an ubuntu box with a single NIC. In order to bind a number of services (like apache, dnsmasq, etc), I have bound them to different alias's (e.g. eth0:0, etc), some of which are on completely ...
3
votes
4answers
240 views

IP forwarding from one interface to another on Debian 7

Background The Debian 7 that I run has the following interfaces wlan3 == Internet connection 85.5.48.64/24 wlan2 == act as an AP (hostapd) 192.168.5.1/24 I run the following settings on the ...
0
votes
1answer
45 views

Run shell script on incoming network package

I have a bit of a weird question. I have a setup where a Raspberry Pi (running that debian) sits next to a door in my office and is connected to the network. The idea now is that if somebody inside ...
0
votes
0answers
29 views

How should I configure my Tor-dedicated firewall for optimum security?

I'm setting up a Tor-based isolating proxy using the 'Anonymizing Middlebox' iptables rules specified here: https://trac.torproject.org/projects/tor/wiki/doc/TransparentProxy i.e. iptables -t nat -A ...
0
votes
1answer
98 views

How do I fix these iptables?

I am trying to setup my networks firewall, and am having trouble because i keep getting kicked out of SSH because of mistakes. Here's what I currently have: # Custom Rules iptables -F iptables -X ...
0
votes
0answers
38 views

Using telnet to router (iptable), set up squid proxy for specific websites and/or from sepcific host

I have a router to which I can telnet. I checked and it allows me to tweak iptable as well. I have a remote VPN running Squid3 which is tested and works fine. Now I want to tell my router by iptable ...
2
votes
1answer
574 views

Mirror Port via iptables

I have a dedicated Linux (Debian 7.5) root server, with a number of guests set up. The guests are KVM instances, and get network access via bridge-utils (NAT, internal IPs, use the host as a gateway). ...
0
votes
2answers
35 views

Why are these iptable rules keeping me from browsing the internet? (allowing 80,443,53)

This is for my home machine. Here are the rules: Chain INPUT (policy ACCEPT 0 packets, 0 bytes) num pkts bytes target prot opt in out source destination 1 ...
0
votes
0answers
292 views

iptables: Allowing multicast & other traffic on LAN, not to WAN

I have a Linux 3.10 machine functioning as a NAT router between the wlan0 LAN and the eth0 WAN. I would like to allow all communication between machines on the LAN (they are trustworthy) and allow ...
0
votes
1answer
60 views

How to share ppp0 to wlan0 with redsocks

I can't understand the meaning of this: I have a USB modem along with a USB Wifi router, and I use redsocks for ppp0. Then I want to forward the incoming connection from Wifi to redsocks. I have ...
0
votes
0answers
18 views

Packets From Inside Not Being Forwared To Outside

I'm trying to forward internal packets to outside without success. iptables -t nat -A PREROUTING -i eth0 -p icmp -d "internal IP" -j DNAT --to-destination "external IP" iptables -t nat -A PREROUTING ...
1
vote
2answers
75 views

How to check/adjust SSH server on embedded board

I'm currently having difficulties connecting to an embedded board from my Linux machine through ssh. The embedded board is a FOX G20 V with a Linux OS. I've tried to connect to the board through ...
0
votes
1answer
63 views

Granular routing with iptables and iproute2 over VPN

On a host at my house I have a host for a VPN that I need for a couple of purposes. Living temporarily in Japan, it functions as a NAT for some devices so I can still use my NETFLIX and some other ...
1
vote
1answer
448 views

iptables blocking all traffic even with ports opened

Simple as I can put it: I can't access my servers with iptables enabled, with default rules. Need to disable iptables to get access. Trying to find the cause. Only difference in setup type is layer3 ...
1
vote
0answers
66 views

Can't connect to web server from outside my network

I have a Debian-based server that I would like to be able to access from the Internet (no domain name yet, I'm just trying to get it working for now). I already have port forwarding set up on my ...
3
votes
3answers
660 views

bridge does not forwarding packets centos

I am using CentOS 6.5 64 and use xen to create a virtual machine (CentOS) ifconfig [root@CentOS ~]# ifconfig eth0 Link encap:Ethernet HWaddr 08:00:27:54:B3:FA inet6 addr: ...
1
vote
0answers
110 views

Conntrack/NAT's port mapping for a specific port breaks whenever that port's service is shutdown for too long. How can I fix this?

Linux Gentoo 3.13.6-hardened-r3 #1 SMP Sat Apr 12 09:17:25 EDT 2014 x86_64 Intel(R) Core(TM)2 CPU 6300 @ 1.86GHz GenuineIntel GNU/Linux hardened with grsecurity and selinux with a strict policy in ...