I've setup ufw rules on my system but noticed that the rule i created to allow traffic from my local network is still dropping some RST packets.here's part of the output of dmesg
[43627.361500] [UFW BLOCK] IN=wlan0 OUT= MAC=00:16:ea:03:9c:3a:00:1f:a7:3d:d5:eb:08:00 SRC=192.168.0.4 DST=192.168.0.3 LEN=40 TOS=0x00 PREC=0x00 TTL=64 ID=2210 PROTO=TCP SPT=59521 DPT=9000 WINDOW=0 RES=0x00 RST URGP=0
[code]....
i have the following system in my lan.
firewall(iptables)
etho(private) - 192.168.2.1
eth1(public) -189.117.57.2
squid server at 192.168.2.10
my request is that i have to make all out bound internet connection should go from proxy server , not directly to firewall. Please specify a iptable rule for blocking direct internet access. my clients ip ranges from 192.168.2.20 to 192.168.2.47
I am currently having problems with my server. Its being DDOSed. I have a vps with Centos 64bit. The attack I want to block is udp flood. I was trying to do something like this: iptables -I INPUT -p udp --dport 123 -m limit --limit 40/s -j DROP but instead of blocking certain hosts it blocks the whole port and during the attack its unreachable. How to limit packets per host or any other way to protect from udp flood.
View 11 Replies View RelatedI have 3 network interfaces on my Linux Router :
Interface - Gateway - Type
Code:
br0 - 192.168.0.1 - Internet
eth2 - 192.168.1.1 - LAN
tun0 - 10.0.0.2 - VPN (via br0)
What I'd like to do is to route all TCP packets coming from eth2 to tun0 where a VPN client is running on 10.0.0.2. If I delete all default routes and if I add a new route to tun0 like :
Code:
route del default
route add default gw 10.0.0.2
Everything is fine, and everyone on eth2 can reach the Internet using the VPN access. Now the problem is that my VPN client does not allow any other protocols other than TCP. And I also want to allow VPN access only to eth2, no other LAN nor the router itself. use iptables to filter any TCP packets and mark them, so they can be sent to tun0, while any other packets can reach the Internet via br0 (192.168.0.1). I found on the Internet that we can mark packets before they get routed. Using the following commands :
Code:
iptables -t mangle -A PREROUTING -j MARK --set-mark 85 -i eth2 -p tcp --dport 80
ip route add table 300 default via 10.0.0.2 dev tun0
ip rule add fwmark 0x55 table 300
First of all, --dport 80 never work... :/ I wanted to filter TCP 80 packets coming from eth2, but none of them seems to be HTTP packets... oO (very strange...). Nevermind, I decided to forget about the --dport option. I use the "iptables -L -v -t mangle" command to see how many packets are marked, and it is working fine, all TCP packets coming from eth2 are marked. Now the problem is that none of them are routed to tun0 they are all respecting the "route -n" rules... and not the "table 300" rule I have created.
I've setup ufw rules on my system but noticed that the rule i created to allow traffic from my local network is still dropping some RST and ACK packets. here's part of the output of dmesg
[Code]...
how can i drop igmp port 0 packets with iptables rule? my log file is full of this router advertisement.
View 2 Replies View RelatedJust wanted input for this script i have cobbeled together. Its not done yet. I am trying to think of ways to close up my outgoing while maintaining full functionality of my laptop ( irc, web stuff, a torrent or two, etc.) . Anyways, I have done some myself; as well as, pulling bits and pieces from other stuff out on the web. I am starting to wonder why i have to write a specific rule to check for spoofed packets if my default input is set top drop. wouldnt it be caught?
Code:
#!/bin/bash
### Laptop + Desktop: No Forwarding firewall ip4 / ip6
### Distro > Debian / Ubuntu.
### oliverteasley@gmail.com
[Code]....
i have a linux server runnig oracle applications. i need to access this server from putty using ssh through internet. i did by registering my static ip with the dnydns.org and i am able to connect to the server. but now there is no security to authenticate any user as any one knowing the password can login to it.
i thought of configuring the firewall of linux server but the client ip`s are not static and they change continiously. so thought of keeping one more pc between the server and the router which will do the work of authenticating. but i am confuse as how to configure it to allow the packets coming from the internet after authenticating and to by pass the packets generated from internal LAN?
i need to write a program in c that can sniff packets from Ethernet and distinguish RTP packets from Non-RTP packets, i have no idea what should i do
View 9 Replies View RelatedQuestion (and Google results aren't making this clear): Ubuntu has both iptables & ip6tables installed. 1. If I set a rule in iptables, does that rule also apply to ipv6, or just ipv4?
2. If "no" to above, then it would be prudent to *also* set ip6tables rules as well if I want to maintain an active firewall, correct?
3. Does ip6tables rules have the same syntax and behavior (more or less) to iptables rules - i.e. can I just copy my iptables rules & change "iptables" to "ip6tables"?
4. Any gotchas or issues that I should be aware of?
I have a hardware device with two ethernet ports, eth0 and eth1 running Centos 5. Basically my goal is to forward packets from eth0->eth1 and eth1->eth0 as well as get a copy of these packets for analysis. If I set IP routing to do the forwarding then I won't get a copy of the packets for analysis.
View 3 Replies View RelatedFor system calls, is blocking or non-blocking default in C? Simple question, just am not seeing the answer super quickly.
View 4 Replies View RelatedI have a device that is working on modbus protocol andI have written a small program(with block TCP read method ) to read its registers via modbus protocol.my program is working very well but except those times that I unplug the Ethernet cable or turning off the modbus gateway during programs work.at this time my program stops on recv system call (if it reach this system call exacly when I unplug Ethernet cable or turning off the modbus gateway during programs work).I changed my source to work in nonblock TCP method, at this time with the same situation my program does not stop/block on recv system call but after pluging back the Ethernet cable or resuming the connectivity situation back it reads data incorrectly .this is my code:Quote:
#define DEBUG
#include <fcntl.h>
#include <string.h>
[code]...
I'm trying to set my network interfaces so that they don't get random every boot.(eg assign eth0 to a network interface with a given MAC addr, and eth1 to the other one)I trew in a udev rule (in fact just modified the rules that was automatically generated and set the ethX in it) but the system ignores my udev rule.What am I missing ?Here is all the info :
Code:
$cat /etc/udev/rules.d/70-persistent-net.rules
# This file maintains persistent names for network interfaces.
[code]....
i'm new in linux world i would like to know how can i add the rtp protocol to my iptables rule for Netfilter firewall,but without installing the asterisk server
View 1 Replies View Relatedi'd like to know how many rule can manage iptable. I'm asking that because i'd to drop all traffric from my localnet to porn site. I've a database of porn site witch contain about 900 000 domains. I know there are solutions like squidguard. But for my linux box i'd to use iptable to prevent users access to porn site and other blacklist site.
View 1 Replies View RelatedUnsure about IP tables lingo, so excuse me for not looking this up:I have a server, running IP tables, that I do not want to allow any type of outgoing traffic to 192.168.1.21
View 3 Replies View RelatedThis is what I have currently running.
Code:
iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT
iptables -A INPUT -m state --state NEW,ESTABLISHED,RELATED -j ACCEPT
[code]...
How do I add this to the ruleset, without doing the whole thing over again?
Code:
iptables -A OUTPUT -d 10.3.0.0/16 -m state --state NEW,ESTABLISHED,RELATED -j ACCEPT
I have 2 LANs in my network. They are:
LAN 1: 192.168.0.0
LAN 2: 192.168.1.0
Both LANs, communicate with each other. And both have an application server. In LAN1, I can access the web server, internal and external. At LAN2, only works on the internal network.The rule that I'm using is as follows: iptables -t nat -A PREROUTING -p tcp -d my_ip --dport 80 -j DNAT --to 192.168.1.254:80
This rule works for LAN1, but not for LAN2. Anyone know what that is can be lockin access?
Loaded up Centos 5.5 final. Configured iptables to block regions of the world based on networks. An example would be:
-A INPUT -s 139.82.0.0/16 -j DROP
My /etc/sysconfig/iptables file contains about 10k entries like this. If I use this, the machine lags hardcore network wise.
Trying to setup my box as a router on Ubuntu 10.04. When trying to setup a NAT rule in iptables 1.4.4 like so:
Code:
sudo iptables --table NAT --append POSTROUTING -o eth0 -j MASQUERADE
I keep getting:
Code:
Can't initialize iptables table 'NAT': Table does not exist (do you need to insmod?)
Looking at lsmod, it doesn't look like I have anything NAT related loaded ( I just have iptable_filter, ip_tables, and x_table ). Doing a locate nat, I find a module that looks like it should work. I'm running 10.04.1 LTS - Kernel is 2.6.32-25-generic #45-Ubuntu SMP and it is pretty much stock - haven't done anything fancy... this module looks promising:
Code:
/lib/modules/2.6.32-25-generic/kernel/net/ipv4/netfilter/iptable_nat.ko
but loading it and I get:
Code:
-1 Unknown symbol in module
This isn't exactly of critical importance, but is there any way to block two entirely different addresses in the one rule, rather than writing individual rules for each of them? For example, if the addresses were 1.1.1.1 and 8.8.8.8, and I only wanted to block these two.
Or alternatively, if I wanted to block two subnets, say 1.1.1.0/24 and 8.8.8.0/24? Can this be done in one rule?
I'm running IPF on solaris 10 Note :i believe the idea will be the same it doesn't matter either its linux or solaris
Code:
bash-3.00# ipf -V #display ipf version
ipf: IP Filter: v4.1.9 (592)
[code]....
my iptables Policy is Drop..my server ports is open just for httpd,ssh .Is there any rule which can allow all connection from a specific program for ex. i want to scan an ip Address ports.as you know nmap connect to every known port to see if that is open or not so, if i want to allow nmap to connect, i need to include all ports for that, or i can allow connection from localhost to outside in all ports .my server is very secure . i dont want other programs (probably a backdoor) use those ports to connect outside i want to know is there any ability in iptables which can rule connections by name of program like "Allow any Connection from /usr/bin/nmap to everywhere " ?
View 2 Replies View RelatedI am new to iptables. The setup tool on a VPS doesn't work. So, I am learning to insert rules. I have inserted so many and some of them show as duplicates now.
1- I want to know how to remove the duplicates. Is there a file that these rules are store in so I can go in and easily edit it?
2- Is there any other utility that handles firewall in Linux that I am unaware of? or is the iptables the ultimate door guard? This is a plain install of CentOS.
3- Since I believe I opened port 5090 but I think it still might be blocked, could SELINUX be the problem? How can I get my way around setting it to permissive or disable if I don't have access to "setup" command?
4- What is the order of iptables reading? does rule #1 supersede all other rules? or does the last rule supersede all rules prior to it?
5- Do the rules below make a fairly safe system? (except for the duplicates which should be remove) I understand that a safe system is dependent also on the applications that are allowed in this category and I am not talking about those. I am talking about dropping all other inquiries and in general is this how iptables are setup? This is what I currently have:
[root@tel ~]# service iptables status
Table: filter
Chain INPUT (policy ACCEPT)
num target prot opt source destination
[Code]...
I am new to Ubuntu almost installed it after windows showed blue screen 4 ever n ever. However after installing ubuntu whenever I log in windows it doesnt detect any network connection but when I use Ubuntu it automatically does can it be that Ubuntu is causing any problem? And how to check how many packets are being sent and received through my wired network and do I have to install any drivers for my modem in Ubuntu.
View 5 Replies View RelatedI am using ubuntu 9.10. Configuring my firewall using guarddog. I have setup a rule to allow traffic OUT on port 7078 UDP, and just because i'm having problems i added an IN rule.
# Create the filter chains
# Create chain to filter traffic going from 'Internet' to 'Local'
ipchains -N f0to1
[code]....
is there any way to point certain packets from my outgoing traffic to a LAN : port ?
can iptables do this ? if yes how ?some like this [URL] ?
My setup is...I have a wireless access point using laptop as a gateway. The AP is also connected to a switch as is the laptop. So the laptop has two interfaces one wireless and one wired. A third device is using the AP to connect to a server on the internet. The AP sends the packets to my laptop where they are dropped. I've been looking for a solution to this problem without success. Basically is there a way for my laptop to forward all packets it sees from a certain IP address to whatever destination address they have?To clarify, my laptop is just the gateway of the AP and none of the packets are addressed to it at all, it just picks them up using a sniffer or similar tool.
View 1 Replies View Relatedusing layer 7 filtering how to block the ftp packets?..
In My router i am going to add a below rule.... iptables -A OUTPUT -m layer7 --l7proto tcp --dport 20 -j DROP
above statement will it work in my router?.