Security :: Block Traffic Initiated From Computers In The DMZ?
Apr 3, 2009I have computers in the DMZ (192.168.1.0/24) .. How to block traffic initiated from computers in the DMZ?
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Security :: Opensuse Susefirewall 2 And My Own Rules - Block Ougoing Traffic Except Some Apps
May 1, 2010I have trouble with opensuse susefirewall 2 and my own rules. since i have installed a suspicious download manager, i detect outgoing traffic in the monitor and i want to block ougoing traffic except some apps like firefox, jinchess ...
1) I had to modify FW_CUSTOMRULES="" with FW_CUSTOMRULES="/etc/sysconfig/scripts/SuSEfirewall2-custom" in /etc/sysconfig/SuSefirewall2
2) I had to add my own rules in /etc/sysconfig/scripts/SuSEfirewall2-custom in the appropriate hook
3) I don't know if rules are good.. they seem to work because for example jinchess can't access his server with the DROP rule until i add the ACCEPT rule BUT in fact the download manager still access internet and amarok too when it searches for songs lyrics ! i have discovered it's because the others apps use port 80
I give here the file /etc/sysconfig/scripts/SuSEfirewall2-custom
How to to make firefox use another specified port ? i wanted to use privoxy with tor but it doesn't work .. is there input/output controler on linux (something like zonealarm on XP) ? the trouble is that all outgoing traffic is permitted by default!
CentOS 5 Networking :: Configure Firewall - Allow And Forward All Traffic On Eth0 And Block All Traffic On Eth1 Except Ssh Ping
Sep 29, 2010I need to set up my centOS computer as a firewall in my home network. Ive got 2 interfaces, eth0 and eth1. I want to allow and forward all traffic on eth0 and block all traffic on eth1 except ssh, ping(icmp) and DNS. How do I do this? Ive tried some editing in /etc/sysconfig/iptables but no luck.
View 1 Replies View RelatedNetworking :: Server To Block All Traffic But US Only Traffic?
Mar 15, 2011I wanted to tell my server to block all traffic but US only traffic. So i followed this guide:[URL].. Now I know, it's the best way to help prevent hackers/crackers (doesn't matter to me what they are called. I just have to stop them). My server only deals with US clients anyways so might as well just start right there for my server's security before getting into the brute force and injection preventions. So I got it all done compiled everything moved to the proper directory. I then started to setup my iptables. Like so
Code: iptables -F INPUT
iptables -F OUTPUT
iptables -I INPUT 1 -s *.*.*.* -p tcp --dport 22 -j ACCEPT
iptables -I INPUT 2 -s *.*.*.* -p tcp -j ACCEPT
[Code]...
After seeing that i went digging in the code and figured it was something todo with memory allocation.
Security :: Iptables State Module - Configuration Error / Not Enable Incoming Packets From Connections Initiated From Inside?
Mar 30, 2011I have a server that I can only access via SSH (it's located far away) and I would like to secure it by blocking all ports except the ones that I need (which are HTTP and SSH). I still want to be able to make outgoing connections to enable software updates and other things.This is my iptables -L -n :
Code:
Chain INPUT (policy ACCEPT)
target prot opt source destination
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
DROP tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpts:1:21
DROP tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpts:23:79
DROP tcp -- 0.0.0.0/0 0.0.0.0/0 tcp dpts:81:65535
code....
In my opinion, this should block all incoming packets except the ones on port 80 and 22, but allow responses to outgoing connections. But a wget http://google.com does not work, it can't establish the connection.
Maybe this is not the best style for iptables rules, but I want to be absolutely sure to not accidently lock myself out from SSH, so I chose not to configure a "block-everything rule".
Does this configuration not enable incoming packets from connections initiated from inside?
Ubuntu Networking :: Monitor Network Traffic (for All Computers)?
Sep 27, 2010what I want to achieve is just to be able to say to who ever is killing our relatively fast connect that they aren't the only person using the network. Everyone just says "I hardly download anything." which is obviously untruthful as normally I can download at 1.5 MB/s but now loading even google.com takes way too long (same with pinging and all other sites). Once I do this, I can determine whether or not I need to call my ISP and do the long 'on hold' dance and "have you tried rebooting the router" BS.
View 8 Replies View RelatedSoftware :: Looking To Block All Non-Tor Traffic
Jan 20, 2010I'm trying to set up my laptop to be as anonymous as possible with Tor. I want to block all non-Tor traffic from leaving the computer. I was looking to find an firewall that filters by PID, so only Tor can send traffic out. Does something like this exist?
I also considered setting up some kind of TUN/TAP interface that tunneled through Tor's SOCKS proxy, but couldn't find anything that does this.
OpenSUSE Network :: Block HTTP Requests From Other Computers?
May 30, 2011My computer shares an internet connection using an ADSL router.There are other three machines.I have set up a Apache server for learning purpose and I want it to be inaccessible from anywhere else including the PCs in the network.When I enter my ip-address assigned in the network (192.168.1.1xx) from other computer,I get my ppages and I dont want that.
How can I block HTTP requests from other computers?
Networking :: Block All Incoming Mail Traffic Except Certain Addresses?
Jan 12, 2009assist me in using the iptables firewall to block all incoming mail traffic (SMTP port 25) except that of a certain IP(s)? the situation is that we have a server that we only want to receive mail from a particular sender.
View 1 Replies View RelatedUbuntu Networking :: Bridging Firewall - How To Block Incoming Traffic
May 2, 2010I have a ubuntu computer set up as bridge between gateway and lan, with the lan connected to eth0 and gateway on eth1.
I'm trying to get it to basically block everything incoming except for the ports i specify, but also allow outgoing traffic. I've found, tried, modified som examples i found on the web, but still it wont block incoming traffic (ie, im still able to reach my webserver)
These are the rules, and i can't figure out why it wont block:
Code:
#!/bin/bash
iptables -F
iptables -X
iptables -I INPUT -i eth1 -j DROP
[Code].....
Ubuntu Networking :: Iptables: Block Incoming And Allow Outgoing Traffic
Jan 6, 2011I need to configure iptables to block incoming traffic (except specific ports), but allows all outgoing traffic.
I am able to block incoming traffic, but doing so also prevents outgoing traffic (tested by telnet [URL] 80)
The following was used:
iptables -A INPUT -p tcp --dport ssh -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j ACCEPT
iptables -I INPUT 1 -i lo -j ACCEPT
iptables -A INPUT -j DROP
Also, even allowing NOT SYN requests still prevents outgoing traffic.
iptables -I INPUT 1 -p tcp ! --syn -j ACCEPT
Another point:
# modinfo ipt_state
modinfo: could not open /lib/modules/2.6.18-028stab070.14/modules.dep
How to install ipt_state module on ubuntu?
Ubuntu Networking :: Program \ Use To Monitor The Number Of Computers That Are Connected To Network And Block Them?
Feb 1, 2011i have recently had a house mate move in and he is using my wireless network, even though i asked him not to give out the network key to his friends either he has or they have hacked my network and are using it when they come over, is there a program i can use to monitor the number of computers that are connected to my network and block them, or is there a way i can just wee what is going on. They seem to just connect and i don't want to have to change the password particularly because that involves changing it on multiple devices.
View 1 Replies View RelatedServer :: PPTP Traffic - Gre Traffic Is Being Generated During The Browsing / Reduce Traffic
Sep 27, 2009Recently I notice that when I'm connected to an vpn server (pptpd) and I'm using it as a default gateway my download and upload speed decreases almost to the half of the usual speed. I made a test using iptables in order to count how much GRE packets are generated (except the real traffic itself) in that way:
Code:
iptables -I INPUT -p gre -j ACCEPT
iptables -I OUTPUT -p gre -j ACCEPT
iptables -I FORWARD -s 172.16.10.101 -j ACCEPT
iptables -I FORWARD -d 172.16.10.101 -j ACCEPT
The first 2 rules match all GRE packets between the pptpd server and client, and the next rules - the traffic between the server and the client.
When I turn the counters to zero and begin to generate traffic (to browse, to download etc.) I see that the GRE packets are even more than these in the FORWARD chain.
So, my question is first of all is my test correct and is it true that so much gre traffic is being generated during the browsing (it becames clear that the traffic is double than if the pptpd wasn't used as a gateway) and if yes - can that traffic be reduced?
Security :: Only Allow Traffic Between 2 Interfaces?
Jun 13, 2010what rules I need to use to only allow traffic between 2 interfaces (which are part of a linux bridge) using ebtables?
So let's say I have if0, if1, if2. I want if1 to communicate with if0. I also want if2 to be able to communicate with if0. But I don't want if1 and if2 to communicate with each other.
Security :: Encrypting All Traffic By Squid
Jun 24, 2010We use a squid proxy server for all http traffic. Is there any way to configure squid so that all traffic which squid and workstation communicates is SSL and encrypted ?
View 2 Replies View RelatedSecurity :: Logging/Blocking LAN Traffic?
Apr 26, 2010Where I work we have a lan, it is almost 100% windows machines except for 2 CentOS machines in which some clients connect to, via VPN. (very small network, <50 ip's used)
I would like to know if there is a way to block access from that machines to others in the network. I'm already logging traffic (with IPTraff) to see if they're accessing other machines in the network others than the ones they should connect.
Security :: UDP Traffic Unauthorized On Ubuntu 10.04?
Mar 11, 2011has my Ubuntu machine been cracked?
machine on home lan
192.168.0.102
it is the DMZ from router
ufw on (ports open for aMule)
sshd installed
[Code].....
Security :: Bypassing ISP Using SSH / Manipulate SSH Packets Between Two Computers?
Sep 1, 2010I setup a SSH server on my computer on a very high port, so that my brother could surf the web through my computer from Iran, since the majority of websites are filtered there.
Today, he told me he cannot connect to my computer. That's why, I got suspicious that they are doing packet based filtering instead of port. Then I decided to change the port to 433 for https, but one of my friend told me that they just banned https in Iran as well.
I was wondering if there's any way I can manipulate SSH packets between two computers so that my brother's ISP won't figure out he's exchanging SSH packets?
Security :: Is A Firewall Needed If Get All Traffic Through A Router
Aug 8, 2010I get all my traffic from my router, as this computer seldom moves. So is there a use for a firewall?I am not sure, because when I scan my IP address with nmap, no matter what the changes I make in the firewall, it is always the same scan...cannot fingerprint OS...and all closed ports.The all closed ports thing only changes when i torrent, then i get a wide open port.
View 14 Replies View RelatedSecurity :: IPTables Setup Blocking SSH Traffic
Feb 11, 2011I set up iptables but it is blocking my SSH set up. I did allow it by opening port 22 but it did not work. Here is my config:
Code:
iptables -F
iptables -P OUTPUT ACCEPT
iptables -P INPUT DROP
iptables -P FORWARD DROP
### this should allow SSH traffic
iptables -A INPUT -p tcp --dport 22 -j ACCEPT
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
How do you allow SSH through the iptables firewall?
Security :: Updates: Specify Source Port For Traffic?
Dec 14, 2010I've a server, and I want to drop all the traffic going out with other source port than 80 (apache) and 22(ssh). The reason is I want to prevent my machine sending packets I don't know (i.e. my server scanning networks or making DDOS attacks without my knowledge). The problem are the updates. If I do what I've said, the updates will not work. I want to allow updates, so I need to let DNS traffic (port 53) and the traffic of the updates to go out.
The problem is the source port. This traffic uses a dynamic port (I think like HTTP). Is there any way to specify a source port to do this? If a have a static port to do this, I would drop all the traffic going out with other port than 22,53,80 and this port.
Ubuntu Security :: Digital Fingerprinting For Computers And Phones
Dec 1, 2010I read in the WSJ today that there is an effort to fingerprint computers and phones. I understand the business model, I'm concerned that too much information will be floating around.
View 9 Replies View RelatedSecurity :: User Names And File Permissions On Two Different Computers?
Jul 23, 2009Picture the following:On computer A, local user John (and John alone) has rwx access to file1.txtComputer B also has a local user account named John. If file1.txt was to be copied from computer A to computer B, would the user account John on computer B be able to access it?I guess this wouldn't work using two windows computers due to the User name / GUID relationship. Maybe linux has something similar?
View 4 Replies View RelatedUbuntu Security :: Program - Network Traffic Monitoring
Jan 31, 2010Is there a program that monitors and displays 'who' is on your wireless Internet signal that one may not be aware of? Like, the ability to see when someone that you don't know is accessing your locked wireless?
View 9 Replies View RelatedUbuntu Security :: Traffic To Specific Sites Throttled?
Sep 14, 2010I want to check if traffic to a specific URL is being throttled by a hospital acting as an ISP. A client is having great trouble accessing a hosted web-app from inside the hospital, but access is fine from outside. The hospital IT dept are not interested as the rest of the Internet is fine. I need to trace where the latency is creeping in or where the throttling is happening, if I can do that, the hospital will remove it. Traffic is standard http to a specific URL.
View 9 Replies View RelatedSecurity :: Will Noise Beat Eavesdroppers Looking For Peaks Of Traffic
Mar 6, 2010we want to post anonymously to a public forum like linuxquestions. We can do it through a service like [URL]. This uses a secure link so any eavesdropper in my LAN cannot see the url I am connecting to.
If this eavesdropper in my LAN suspects I am posting on linuxforums.com, they can look at times when my suspected posts appear in this public forum, and compare them with peaks in the traffic from my computer, and if the times match, it's a strong indication I am the same person. If I somehow fill the virtual private connection with a dummy data stream, can the eavesdropper still tell I am posting to linuxquestions?
Ubuntu Security :: Firewall: Completely Prevent Any Traffic From Network?
Jan 4, 2010I have Ubuntu 8.04 as virtual host. On this host I have installed VirtualBox virtualization software. I have installed Windows XP as virtual machine and installed HTTP server.I would like temporally disable all network connections to host and virtual machine.So on Ubuntu host I have set firewall settings:
Code:
sudo iptables -F (to flush - delete all firewall settings)
sudo iptables -P INPUT DROP (to disable all input traffic)
[code]....
Ubuntu Security :: Home Network Traffic Monitoring Recommendation?
May 9, 2010I was reading a magazine article today which was a discussion of internet detective work for tracking down ip addresses which attempt an ssh login to your machine. I have never really paid much attention to network security since I only run a small home network. I have WPA encryption and a firewall on my router. But while reading this article, I remembered that I myself has seen log files in the past that inidicated someone somewhere had attempted to log into my machine (attempts all failed). This had happened a few times, but I never really considered it a threat.
But, the more I read about home computers becoming "zombies" for criminals, I guess I am getting a little paranoid in my old age, particularly since my wife does quite a bit of business on the net with credit cards. I have four computers connected to the net and each other on this network, and would like to be able to easily detect attempted log ins and deal with them quickly.
So my reason for posting is to ask if someone could recommend a novice-friendly application for monitoring traffic to check this intermittently. I have read bodhi.zazen's excellent tutorial on snort, but I it appears to be written for large lan's or web servers and is over-kill for a small home network.
Ubuntu Security :: Reject Versus Drop For Outbound Traffic
Apr 15, 2011I understand the difference between Reject vs Drop for incoming traffic, but are there any differences between reject and drop for Outbound Traffic? Are there reasons to pick one over the other or are they functionally identical when talking about Outbound traffic?
View 6 Replies View RelatedUbuntu Security :: Unusual Traffic From Amazon EC2 Cloud Server
May 1, 2011Last night my old Sony Vaio laptop which connects via wired Ethernet and runs Ubuntu 10.10 started hammering the network out onto the Internet. Fired up Wireshark and found lots of traffic between my machine and 174.129.193.12 which I did a whois on and found belonged to Amazon EC2 Cloud Server. The port on my machine was an unknown 5000+ but the port on the remote system was 443 the port used by https, however no browser was running. Did a search and put together a couple of iptable commands to block this IP address which stopped the traffic. I then used nmap and netstat and found port 3000 open and another connection to IP address 91.189.89.76 which I also blocked. Unusually no info exists on this IP when you do a whois. At first I thought it might be some sort of sync as this machine has Ubuntu One running on it, however it could also be something else.
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