iptables allow creation of rules to define packet filtering behavior.

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240 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 ...
3
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1answer
167 views

How to deny access to specific port when destination is NOT a specific host?

I'm trying to DENY access to port 1000 when it is being accessed through any host or IP that is NOT a specific host. I.e. If I try to access the service on sub.domain.com:1000 I should get in. If I ...
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0answers
163 views

Cloning packets with iptables

I can't figure out for sure, is there a way to clone packets with iptables on one machine? I have an UDP stream to the specific addres (e.g. 192.168.207.201:9702) and I want to do some processing on ...
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1answer
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IPTABLES is slow after adding '-A INPUT -j DROP' to rule list

I am just getting started with iptables and stumbled across something I don't really understand. FYI, I followed the instructions of Ubuntu wiki's IptablesHowTo. The nat and mangle tables are empty, ...
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3answers
3k views

iptables-restore just says “FAILED”

I am not sure what's wrong with my rule in the Iptables. I am actually trying to build a SSH server and following a cyberciti tutorial. My Iptables configuration looks like this: # Firewall ...
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1answer
53 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 ...
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2answers
165 views

RELATED,ESTABLISHED state in iptables

What do the words 'RELATED' and 'ESTABLISHED' individually signify in RELATED,ESTABLISHED state in iptables?
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1answer
6k 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, ...
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2answers
222 views

How can I prevent iptables from counting bytes and packets on empty chains?

Background I occasionally have firewall rules that I need to use for maintenance windows, but don't want active (and therefore consuming CPU cycles or slowing the network interface) the rest of the ...
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2answers
2k views

Block specific application with iptables [duplicate]

I have to harden a Linux desktop as an assignment in my college. But I got stuck at a specific problem: I have to control the outgoing traffic with iptables. It should be possible to prevent a ...
2
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1answer
211 views

pptpd dead but subsys locked? on cent os

i install point to point tunnel (PPTP) in my VPS. (Cent OS 6 64 Bit) everything fine after reboot the PPTP not worked client side. the pptpd status shows " pptpd dead but subsys locked ". how to ...
2
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1answer
270 views

No internet even with iptables ACCEPT all

I was trying to setup the firewall settings, and probably did something wrong. I don't have internet now unless I stop iptables service I tried flushing,and accepting everything sudo iptables -F ...
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2answers
915 views

iptables: The “script” way or the “*filter, rules, COMMIT” way?

I'm trying to figure out how NAT and iptables work. While I'm in the trial-and-error phase of learning about it, I found two somewhat conflicting howtos. One howto uses a script to call iptables ...
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2answers
174 views

How is the loopback device traffic allowed?

How can I allow the traffic to be sent on the loopback device (lo)? What is the iptables command for it?
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1answer
399 views

iptables couldn't load target allow

I am using the command below to allow all traffic from hosts on my internal network but it says "iptables v1.4.18: Couldn't load target `ALLOW':No such file or directory". What is the problem here? ...
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1answer
358 views

Archlinux not configured with iptables

I have been trying to set up iptables on my archlinux server, however when I run iptables -nvL I receive the error iptables v1.4.20: can't initialize iptables table 'filter': Table does not exist ...
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0answers
329 views

Route all HTTP traffic through polipo

I've set up polipo on my machine to listen to the default port 8123. To test it, I set the in-memory cache to a ridiculously high 2 GB and downloaded a 50 MB file using wget utilizing the proxy. ...
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2answers
527 views

Route wlan0 to openVPN tunnel and rest to eth0

I'm having problems to create route/iptables rules for following configuration: I have an openVPN server (tun type) running on my raspberry machine at home At work i have company pc (behind proxy) ...
4
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1answer
101 views

How do you do NAT port redirection with PF?

In Linux, you can do NAT port redirection with a command like this: iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j REDIRECT --to-port 8000 What is the equivalent with BSD's PF?
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1answer
208 views

iptables - why the stun, turn ports are not working to allow end points to access the server?

I have this iptables where all working except tcp/udp port 3478 and 5349. $ cat /etc/sysconfig/iptables # Generated by iptables-save v1.4.7 on Thu Nov 21 10:21:41 2013 *filter :FORWARD ACCEPT [0:0] ...
2
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1answer
90 views

Port forwarding using iptables on Linux

I want to forward a local port to a remote port (8041) to a port (8042) on a remote machine (10.0.0.42). I can do this via ssh -L 10.0.0.41:8041:10.0.0.42:8042 user@localhost where 10.0.0.41 is ...
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1answer
217 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 ...
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3answers
3k views

route traffic out different gateway by destination network

I have several gateways and would like to route some traffic out of different gateways based on its destination. I'm guessing I'd need to use a combination of iproute2 and iptables rules, but am not ...
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0answers
550 views

Fail2ban - alternative robust for enterprise protection against DoS attack in SIP and similar to fail2ban features

Is there any fail2ban like software for CentOS 2.6.32-358.6.2.el6.x86_64 ? (fail2ban is 0.8.10 installed) but its slowing down the system completely, i was looking for something which can be similar ...
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0answers
224 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 ...
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2answers
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iptables: rules for tftp server

I have a tftp server which listens on standard UDP port 69. I have added following rule to my iptables to block everything except UDP 69. -A INPUT -i eth0 -s 192.168.1.0/24 -p udp -m udp --dport 69 ...
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2answers
101 views

Modifying one line in Iptables

How would one modify the following line in iptables file (debian)? ACCEPT all -- XXX.XXX.XX.X anywhere PHYSDEV match --physdev-in vif3.1 TO ACCEPT all -- ...
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1answer
185 views

Bandwidth throttling per user group

I am wondering if it is possible to create a bandwidth shaping/throttling script that shapes traffic based on user group. That is, if user1, user2, are in user group group1, they will have 1mb/s ...
0
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1answer
380 views

iptables rules for iscsi initiator

I need to configure iptables on my client (iscsi-initiator). From tcpdump, I can see that the server (iscsi target) sends tcp from port 3260. So I have added following iptables rule on my client ...
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0answers
301 views

destination IP mangle table

I have machine with 2 interfaces: eth1 connected to internet (ip xx.xx.xx.xx) eth0 connected to my laptop (ip yy.yy.yy.yy) I add those lines to the firewall file in order to manage the bandwidth ...
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2answers
459 views

fail2ban log parsing too slow on Raspberry Pi - options?

I'm running fail2ban on a Raspberry Pi at 950MHz which I cannot overclock further. The Pi is occasionally subject to SYN floods on particular ports. I've set up iptables to throttle the rate of SYNs ...
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136 views

prioritize traffic for some bridge interfaces using prio qdisc

Im configuring my router to give preference to some WAN interfaces. This interfaces are named ppp0 (PPP interface), vc2 (RFC1483 bridge interface) and vc3 (RFC1483 bridge interface). I had understood ...
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1answer
1k 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 ...
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1answer
249 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) ...
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1answer
137 views

Managing iptables for home lan routing

I have a LAN at home. One Netgear router - 192.168.0.1 connected to the internet. One Macbook - 192.168.0.10 (connected to Netgear router) One PC with Kali Linux - 192.168.0.20 (connected to ...
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2answers
459 views

How do I fix iptables in ChromeOS?

Using the shell in chrosh in ChromeOS I followed some (apparently terrible) advice to flush my IP tables. using the command sudo iptables -F I am now unable to connect to the internet at all. All ...
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2answers
79 views

ipset accounting information

I know that iptables keeps accounting information for ip traffic blocked or passed. However, it appears that when using ipsets with iptables, the accounting information is aggregated for the entire ...
3
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1answer
2k 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 ...
4
votes
1answer
6k 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 ...
0
votes
1answer
144 views

Squid not forwarding my packets proxied from iptables on router

I am trying to make openwrt's iptables from my router to direct to my squid proxy on my machine (since there is no enough space in router's flash memory) but even if I have my squid config ok ( ...
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0answers
25 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 ...
1
vote
1answer
103 views

Where does Iptables store blocked IPs

I need to set up a shell to block DDOS attacks , but in that script, it's reading some Blocked IPs from /etc/sysconfig/iptables. The problem is that I don't have this directory, So I'm wondering ...
0
votes
1answer
2k views

How to redirect to my squid proxy using iptables since DNAT target: only valid in nat table

I want to redirect the traffic in my lan network through squid proxy but I am having some problems with iptables rules. When I use the following rule: # iptables -I FORWARD -s ...
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4answers
758 views

Failing to block brute force ssh with iptables

I'm trying to block (slow down) brute force attacks on my sshd server. I'm following this guide http://www.rackaid.com/resources/how-to-block-ssh-brute-force-attacks/ which basically says I need to ...
0
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3answers
144 views

Search in iptables.log file takes a long time

I have used iptables to save information about connections by modifying the /etc/syslog.conf file to save information in /var/log/iptables.log. So, every X hours, I need to extract information from ...
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2answers
451 views

CentOS restore firewall after `service iptables panic`

My friend and I were doing some firewall configurations and in the meanwhile he thought it was a good idea to type service iptables panic. Now we cannot put the firewall back on the original state ...
4
votes
1answer
453 views

Why is my computer trying to send ICMP type 3 to OpenDNS?

In my firewall logs I see lots of entries like this. IN= OUT=eth0 SRC=192.168.1.105 DST=208.67.220.220 LEN=148 TOS=0x00 PREC=0xC0 TTL=64 ID=55705 PROTO=ICMP TYPE=3 CODE=3 [SRC=208.67.220.220 ...
8
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2answers
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Iptables to allow incoming FTP

i want to allow incoming FTP traffic. CentOS 5.4: This is my /etc/sysconfig/iptables file. # Generated by iptables-save v1.3.5 on Thu Oct 3 21:23:07 2013 *filter :INPUT ACCEPT [0:0] :FORWARD ...
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vote
1answer
1k views

iptables redirect FORWARD http traffic to privorxy port

Ideally i m trying to use my laptop and a 3Gphone as a WiFi router to redirect FORWARD HTTP but not HTTPS Traffic to privoxy which then forwards the traffic via a SSH tunnel to a ziproxy VPS. for the ...
4
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1answer
66 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 ...