3
votes
1answer
57 views

Configure iptables on remote server without locking me up

I have a little remote server that I can access only with SSH, and what I want to do, is block all the traffic except port 22 for SSH. The first time, what I did was : iptables -P INPUT DROP And ...
0
votes
4answers
48 views

Linux routing tables

I'm trying to learn Linux routing tables and ran into bit of snag. In the example below I'm not sure what is happening. My understanding is 0.0.0.0 means that for line 1 and 2 any packets outside of ...
1
vote
1answer
26 views

How to see content of dropped packages at OUTPUT chain in iptables

iptables is as below: # iptables -t filter -nvL Chain INPUT (policy DROP 0 packets, 0 bytes) pkts bytes target prot opt in out source destination 0 0 ...
1
vote
1answer
42 views

iptables adding rules in OUTPUT chain

We can insert iptables rules based on IP/Network/Hostname: iptables -t filter -A OUTPUT -p tcp -d www.google.com -j ACCEPT -m comment --comment "www.google.com" It is not accepting: iptables ...
1
vote
1answer
29 views

FTP download problems with iptables — Port 21 connection is allowed but “Network is unreachable”

I'm trying to connect to an FTP site but with, e.g., wget: Logging in as anonymous ... Logged in! ==> SYST ... done. ==> PWD ... done. ==> TYPE I ... done. ==> CWD (1) /gcrypt/gnutls ...
0
votes
3answers
43 views

iptables rules - input and output

I'm new with Linux and iptables. I have a Ubuntu Server distro (12.04) on a PC which has 2 network interfaces (eth0 and eth1). I also have 2 laptops, one is plugged to eth0 and the other to eth1. ...
2
votes
1answer
27 views

Should IP tables rules affect a serial port on Linux

I'm trying to setup some iptables rules on my embedded Debian Linux system, using a serial console I entered this: root@ts7600-47aad3:~# iptables -F root@ts7600-47aad3:~# iptables -P INPUT DROP ...
0
votes
0answers
225 views

IPTables “iptables table `filter': Table does not exist (do you need to insmod?)”

I'm trying to get iptables working for my embedded Debian system, kernel version 2.6.35.3-571-gcca29a0. I've tried to enable iptables support in the kernel by selecting these options (this is a diff ...
1
vote
2answers
40 views

Run shell script based on IPTABLES port access attempt

Is there a way in Linux (RHEL 5-6) using IPTABLES, that if someone tried to access port 21, as an FTP user, to log what the user name they are trying to authenticate as and additionally run a shell ...
0
votes
1answer
118 views

how to forward from port 80 to 8080 using iptables without opening port 8080?

The following iptables configuration work for forwarding port 80 to 8080. #nat chains *nat :PREROUTING ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] :OUTPUT ACCEPT [0:0] -A PREROUTING -i bond1 -p tcp -m ...
2
votes
1answer
42 views

Randomizing the source port for new connections

Generally whenever source port is selected by a network application, it is selected in a sequential manner among the free ports like 32000, 32001 and so on. I want to randomize the source port ...
0
votes
0answers
25 views

Routing Application through different network interfaces [duplicate]

I have two interfaces on a server, let's call them eth0 and eth1. The underlying server is running CentOS 6.5 I would like to be able for some application to use eht0 while some others use eth1. ...
1
vote
0answers
40 views

setting up a local VoIP to use as a Wifi Headset

I had this idea of using Wi-fi in a vehicle to connect my cell to the car call handler.Just as it works with bluetooth nowadays. Just to demonstrate that such a thing is possible , i had three Linux ...
3
votes
1answer
129 views

listen to a conversation using port forwarding

I have been able to make a phone calls using the SIP client Pjsua from one Linux computer to another one. In case you have not heard of this user agent, explaining it's functionality is quite easy. It ...
0
votes
1answer
47 views

Configuring iptables by software

Is there a software, or a linux distro which has such a software built-in, which makes configuring the iptables easier? If not, I thought that some of the mostly used configuarations with a simple GUI ...
3
votes
1answer
1k views

How to Allow Outgoing SMTP on iptables Debian Linux

If I choose to allow all traffic on the OUTPUT chain (iptables -P OUTPUT ACCEPT) mail sends fine. As soon as I lock down my server with these rules, outgoing mail stops working. All else works though, ...
1
vote
1answer
127 views

Session limit for OpenSSH server on Ubuntu Desktop 7.10

I need restrict session limit on my OpenSSH server only for one session (one connection). I use Ubuntu Desktop 7.10. Of course Version is old, but I need it for experimental purposes. I tried modify ...
2
votes
0answers
199 views

iptables REDIRECT in combination with matching on interface vs. IP address

I've successfully set up Tor for transparent proxying using iptables (ie, all outgoing traffic is sent through Tor without the application's knowledge). In doing so, I discovered both an odd problem ...
2
votes
1answer
576 views

Linux Fedora 19 - iptables failed to start

I've been trying to start the iptables firewall service, but it keeps failing. What's going wrong? # systemctl status iptables.service iptables.service - IPv4 firewall with iptables Loaded: loaded ...
1
vote
1answer
153 views

How do I allow only certain IPSet set's to access a certain port with iptables?

I'm using IPSet to build IP ranges for different countries as follows : # Canada ipset -F ca.zone ipset -N ca.zone nethash for IP in $(wget -O - http://www.ipdeny.com/ipblocks/data/countries/ca.zone) ...
3
votes
1answer
457 views

What is the difference between OUTPUT and FORWARD chains in iptables?

CentOS 6.0 I'm studying iptables and am getting confused on the difference between FORWARD and OUTPUT chains. In my training documentation, it states: If you're appending to (-A) or deleting ...
3
votes
1answer
2k views

How can I configure syslog.conf file, to log iptables messages in a separate file?

How can I configure /etc/syslog.conf file in order to save log information about iptables in a specific file. I want to save these information separately, so I can extract what I want easily and ...
1
vote
0answers
23 views

Configure syslog.conf file [duplicate]

How can I configure /etc/syslog.conf file in order to save log information about iptables in a specific file. I want to save these information separately, so I can extract what I want easily and ...
0
votes
2answers
125 views

Search in iptables.log file

I have used iptables to save information about connections. So i have modified /etc/syslog.conf file in order to save information in /var/log/iptables.log. So, every X hour, i will extract ...
4
votes
1answer
64 views

Is there any difference between these two configuration options?

Is there any actual difference between iptables -P FORWARD DROP and net.ipv4.ip_forward = 0 ? I know that one is a firewall command while the other one is a kernel option. But: I don't know ...
2
votes
1answer
278 views

iptables port forwarding

I have a CentOS server with Java/J2EE(Tomcat) installed on TCP port 8080. I have two interfaces, eth0 and lo. I need to forward all incoming connection on TCP port 80 to 8080. I tried doing the ...
0
votes
2answers
180 views

Isolate a hosts networking with iptables

I want to isolate a host on my home intranet using iptables on my linux router. So say for instance, I have a host that has the IP of 10.0.1.50 and I want it to be able to talk to the rest of the ...
2
votes
1answer
48 views

How would I go about making this IPTABLE rule for every ip and not just one?

iptables -I PREROUTING -t nat -p udp -s 192.168.0.62 --dport 53 -j DNAT --to-destination 23.21.182.24 Instead of 192.168.0.62 I'd like to set that as a global rule, EVERY ip that needs dns should ...
2
votes
0answers
177 views

SNAT problem in iptables

I am trying to reroute traffic from specific devices in my house over openvpn. For this, I've created an OpenVPN tunnel between my house wifi router and my server. Here is my setup: Wifi router's ...
8
votes
1answer
662 views

Linux as router with multiple internet providers

Linux as router: I have 3 Internet providers, each with its own modem. Provider1, which is gateway address 192.168.1.1 Connected to linux router eth1/192.168.1.2 Provider2, gateway address ...
1
vote
1answer
113 views

Redirecting all IP over USB traffic to a fixed address

I'ma bit of a network newbie, so apologies for the inaccurate vocabulary. Say I have a device connected by IP over USB to my computer (running Ubuntu), that connects to 10.0.0.1. I configured my ...
2
votes
2answers
1k views

Debugging iptables using live packet views

Are there any CLI or GUI functions that I can use to monitor hits to iptables and watch as packets interact with iptables?
1
vote
2answers
199 views

iptables: what the difference between filter and mangle

I am using iptables to to mark the package and want to route based on the marks. First I added the ip rule: sudo ip rule add fwmark 1 prohibit (The "prohibit" is just for test, I will change it ...
0
votes
1answer
200 views

Allowing a domain name in my IP Tables

I have a Linux server that gets a time offset for some strange reason. I set up cron job to run and update the time using the following command: /usr/sbin/ntpdate pool.ntp.org The problem is the ...
1
vote
1answer
167 views

port forwarding to internal lan server

I've ppp0 --> eth1 and eth0 (internal lan). I need forwarding externel 10022 port to port 8999 of the server 192.168.1.254 iptables -t nat -A PREROUTING -p tcp -i ppp0 --dport 10022 -j DNAT --to ...
1
vote
2answers
409 views

SSH tunneling through a busybox router

I have a busybox router and I'm able to login to the console using telnet & I also have access to the web interface. My question is, how can I create an ssh tunnel from my local network through ...
2
votes
1answer
228 views

IPTables string match redirection

The issue: I am currently redirecting port 80 requests to another system on port 1000. This is done like so: iptables -t nat -A PREROUTING ! -s 172.20.1.2 -p tcp --dport 80 -j DNAT --to-destination ...
1
vote
1answer
390 views

How does iptables MASQUERADE work on the incoming side?

I'm still reading the iptables manual page and other documents and digging around questions and their answers. This is the problem which arises. When we setup the NAT we use a POSTROUTING rule such ...
3
votes
1answer
3k views

IPTables - Port to another ip & port (from the inside)

I currently have a NAS box running under port 80. To access the NAS from the outside, I mapped the port 8080 to port 80 on the NAS as follow: iptables -t nat -A PREROUTING -p tcp --dport 8080 -j DNAT ...
2
votes
1answer
233 views

Can iptables be used to convert a single-homed host into a NAT server?

Given: I have a machine (HostA) with only one NIC which has Internet connectivity. I have another machine (HostB) with one NIC on the same switch. HostB is not configured for Internet access yet. ...
2
votes
2answers
4k views

Where is iptables script stored on DD-WRT filesystem?

I have an ASUS RT-N16 router that I've flashed with the open-source DD-WRT firmware. According to my ssh login, I'm running: DD-WRT v24-sp2 mega (c) 2010 NewMedia-NET GmbH Release: 08/07/10 (SVN ...
1
vote
1answer
354 views

How do I route different users over different OpenVPN tunnels in Linux?

The setup: I have multiple, static-key OpenVPN client/server configurations, labeled "client1", "client2", and "client3" with server/client IPs 10.10.1.1/10.10.1.2, 10.10.2.1/10.10.2.2, and ...
2
votes
1answer
162 views

Explanation of bandwidth management script calling tc

I have some scripts in Linux to manage internet bandwidth, but I do not understand what they do. What is the meaning of the following scripts: tc qdisc add dev $IF root handle 1: htb default 256 tc ...
3
votes
1answer
423 views

tc on bridge port

I have a 4 port bridge: root@Linux-Switch:~# brctl show bridge name bridge id STP enabled interfaces br0 8000.000024cd2cb0 no eth0 eth1 ...
9
votes
4answers
1k views

Block network access of a process?

Is it possible to block the (outgoing) network access of a single process?
2
votes
3answers
7k views

How can I redirect ports 80 and 443 to 8080 and 8443 with iptables?

I'm looking at the documentation for a Tomcat 6 webapp called DSpace, specifically in regardds to running Running DSpace on Standard Ports (80 for http:// and 443 for https://) I am trying to use ...
2
votes
1answer
240 views

IPtables command shows libipt_random.so missing

When I run a command, it shows error. I searched on net, but no one give me the correct answer. Googling shows only wrong answers for this questions. So please help me to overcome this problem. ...
1
vote
1answer
696 views

Help to understand Iptables Forward chain with DNAT

I have one server where iptables configured with all chains DROP in filter table eth0 :- 10.0.0.2 [ Intranet assume as LAN ] eth2 :- 172.16.0.2 [ External clients assume as WAN ] Now What I am ...
2
votes
1answer
173 views

Linux nat/iptables configuration for a chain of peer-to-peer links

I have an experimental setup, of 4 Linux (CentOS) machines: All 4 machines are internally connected using different networks and can ping eachother directly connected interfaces. However only PC4 ...
1
vote
2answers
2k views

iptables blocking from internet side on eth1?

How to use iptables to deal with two Ethernet ports? eth0 port for LAN use (192.168.1.50 Private IP). eth1 port is connected to the internet via cable modem (80.0.xxx.xxx public IP). ifconfig ...