I wish to prevent some programs from "phoning home", and to allow other programs to access only specific web servers.Is there any way to interactively allow or decline outbound communication from individual programs on Ubuntu?
View 4 RepliesI need to log outbound (server -> remote) ssh traffic, but am unsure of the best way to do this.
I added this to iptables, but nothing is being written to the logs when I ssh from the server to another system.
iptables -A OUTPUT -m state --state NEW -j LOG --log-uid iptables-save
Got 3 computers connected by ethernet to a router modem. At this router modem only port 80 is forwarded to a web server (one of the 3 computers). Now I realized several times a port scanning attack displayed at interactive firewall of Webserver ( Apache at Mandriva LINUX ). Actually the message is port scanning attempt of heanet (actually this names are different mostly). I wonder how to figure out is this portscanning attack possible through port 80 or is the modemrouter (Draytek VIGOR) misconfigured, compromised or one of the other 2 machines (Windows) are compromised and attacking the server inside intranet?
View 2 Replies View RelatedI 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 RelatedIs there a way to configure my interface to promisc mode and also make it not capture the "transmitted" packets. ?I mean, i want the interface in Promisc mode but only for inbound traffic.If there isnt any using ifconfig, can it be by configuring eth0 to promisc using ifconfig , and filtering outbound traffic from being captured using sockets or something ?
View 4 Replies View RelatedI 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 RelatedI've read up some of the posts on this forum, but can't seem to find an answer. I have a web service within an Apache Tomcat instance installed on a Redhat linux server. I only have shell access to the server, and need to monitor outbound network traffic from my web service. Is there a unix command that will allow me to monitor all outbound traffic? I'm thinking fiddler, but a unix version? I've heard of things like ntop and iptraf, but I don't think those will help me in this instance.
View 2 Replies View RelatedWhat should I do to keep important files on my computer from being uploaded to the internet? Don't I need an outbound firewall to prevent this?
What causes my computer to send an outbound request to the internet that would result in files being uploaded from my computer onto the internet? I'm afraid to put anything of importance (like reports that I've written for work) onto a computer with internet access because I don't want them to be uploaded to the internet. I wouldn't upload them on purpose obviously, but I'm afraid it would happen without my knowledge because I don't know what I'm doing.
Using Windows, I always set a Restrictive firewall policy with a third party firewall. But I also had all ports set to Stealth, something that appears to not offer any security benefits (as I've learned from reading Ubuntu forums). I'd like to learn about best security practices (under Ubuntu) for outgoing firewall protection. I will be using the built-in Ubuntu firewall that is configured via Firestarter. Outgoing filtering offers privacy as well as security benefits. But I thought I needed my ports stealthed to be safe too, so I'm open to learning new things.
I wanted to start a poll to find out how many folks use permissive/restrictive, but no polls allowed here apparently.Could Ubuntu users knowledgeable about firewalls enlighten me on whether I should go Outbound-Restrictive and what applications I will need to allow so Ubuntu "housekeeping" is not affected negatively? I basically just use the internet for software updates, web-surfing and e-mail. One question I have is whether there is something comparable in Ubuntu to Window's "DNS Client" service? I always disabled Window's "DNS Client" and forced each application to request port 53 DNS lookups itself.I only had to allow four programs to accomplish all internet traffic that I engage in. I set all other programs/applications to be either Blocked or to have to Ask for an outgoing connection as needed.Here is my former Windows XP setup:
svchost.exe: allow UDP for ports 53, 67, 68, 123 (time) and TCP for ports 80, 443
Avast: allow UDP for port 53 and TCP for port 80
firefox: allow UDP for port 53 and TCP for ports 80, 443
IE: allow UDP for port 53 and TCP for ports 80, 443
I have problem on VPS running opensuse. When I enable firewall outbound connections stop working. I have tried everything I know (not much when it comes to firewall (iptables)) but could not solve this.
Here is my ifconfig:
Code:
I used xxx.xxx.xxx.xxx to hide real address.
I'm having an issue where a server in CA (1000/full) and in VA (100/full) have very lopsided data transfer.
CA -> VA with iperf shows ~20Mbps
VA -> CA with iperf shows ~93Mbps
If we change the CA server to 100/FULL, transfer speed is 93Mbps both ways.
Some tuning was done to TCP window scaling parameters, but it won't correct the issue, just improve the CA -> VA numbers to what is listed above. I will say, turning TCP window scaling OFF will lower the transfer speed both ways to < 20Mbps.
The only clue I have when looking at wireshark dumps is that the window scale going OUT would never go past 10240 (scale is 8, so 2^8 x 40bytes). In the opposite direction, the window size will go above 3MB (scaled).
It is not a bandwidth problem as iperf with UDP shows 93Mbps both ways. Local transfers (CA 1000/full to CA 100/full) show full speed both ways, so I feel it is strictly related to TCP window scaling.
RedHat 5 64-bit on both sides. Any ideas why it won't scale above 10240?
I 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 RelatedI 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]....
I have a server on my router on the DMZ. All outside traffic goes to it. This server has Apache running and the domain mysite.com resolves to the the DMZ web server. I have a second server on the LAN that also has apache running. I want to set up another domain, myothersite.com to resolve to the second server on the LAN. Since the main server is on DMZ I have the DNS A records for myothersite.com pointing to the public IP that the DMZ is on.
How do I get myothersite.com to resolve to the second webserver on the LAN? What configuration do I need to do on my DMZ server so it routes traffic for myothersite.com to the other server on teh LAN? Do I use BIND DNS? If so please advise on how to set that up. BIND DNS seems confusing and I having trouble knowing how to configuring it. Is there another option besides BIND?
I 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].....
I have installed the graphic user interface for IPtables and enabled this firewall. However, I find it a bit strange. What is the difference between rejecting and denying the traffic? If I want to configure IPtables as two-way, how can I define which of my apps can connect to the internet and which can't? If this firewall is enabled, does it really run in the background, protecting the user,or does it run only when its GUI is opened?
View 9 Replies View RelatedI am looking for a solution for our LAN traffic monitoring and would like to use some opensource linux application. I have a linux box with two NIC cards and what I thought is the following: Our setup is as follows. Internet comes in through the router and into the firewall. From the firewall it goes into our switch and distributed among the workstations.
I have no access to the router or the firewall as they are centrally configured. I would like to place a device into the loop through which I could monitor the LAN traffic.
Can I put a linux box between the firewall and the switch and have all packets going through registered and logged? I have a proxy server (non transparent) and that captures some but not all. I would like to get all packets registered without interfering with the LAN etc.
Does anyone know if it is possible to filter/block network traffic between internal hosts on a lan?
Eg. : Linux firewall/router ( 192.168.0.1) - LAN Default G/W - all internal > external traffic gets filtered.
How would you filter tcp/ICMP/UDP traffic from internal host a ( 192.168.0.2 ) to host b ( 192.168.0.3)
All the internal hosts have the linux f/w as the default gateway, and are all on the same /24 subnet.
I would like to know if I can filter traffic between internal hosts.
I have a question, on my firewall at work I am seeing a constant flow of denies from many different source IP addresses, of tcp/udp destination port 53372 & 53375.What in the world is that, and why these two ports over and over
View 1 Replies View RelatedRecently 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?
(centos 5.5 86*64 with cpanel) I am trying to set up a php script.
The script requires an outbound connection to project honeypot and when I go to the honeypot.php on my server I get an error asking if outbound connections are disabled.
They could be...I am not sure where to check, I have checked csf and outbound tcp is allowed on port 80, but I am not sure if I should be looking somewhere else.
Obviously I dont want to make the server insecure, so I am wondering how I can allow this outbound connection.
My setup is local install so I don't expect it to receive emails from the internet.However I do expect it to be able send messages to the internet, but it doesn't seem like it. I have tried setting up on FreeBSD before and it was able to do so but I wasn't involved in the setting of the machine though. I was just tasked to setup Horde
View 3 Replies View RelatedI want to prevent code from making http connections to other, specific hosts. My understanding is this can be done in /etc/hosts.deny. What would that look like?
View 5 Replies View RelatedI have a situation where I am in a non-interactive shell. I have tried from within my non-interative shell to spawn an interactive shell but my output still does not goto me. Isn't there a way I can somehow go into /proc or somwhere and make the output my /dev/tty1? Or some way else to remedy this?The situation arises because I drop from my restricted shell environment (a sort of CLI interface), into the actual Linux shell. I cannot change the code of the CLI environment I am just faced with being in the linux shell environment and its non-interactive. Its very annoying to have to put > /dev/tty1 after every command I type.
Not to mention it seems damn near impossible to get pagers like more and less to work properly when your in a non-interactive shell.
Is there a non-interactive way to change a user's passwd short of using expect? I'm using Debian.If not, then I guess I need to get this expect script working:
Code:
#!/usr/local/bin/expect -f
set username $env(UNAME)
[code]...
how can I make my sh interactive by default. That I don't have to always type --interactive everytime I log in. I want it to be always interactive. #2- how also do I turn of --posix mode parmanently ? Is there a line I need to drop somewhere or what do i do.
View 4 Replies View RelatedWe have something on our network that is reaking havoc with our content filter. I am trying to track it down, but so far I have been unsuccessful. We have approximately 500 devices in 100+ different locations spread across 9 states. Looking at each computer is not really feasible.
I need a machine that can sit in between our network and our internet connection and graphically monitor in real time and logs how much traffic each device is sending and receiving. It would need to sit inline so it has to have two nics and be able to pass traffic. The machine also needs to be transparent. Reconfiguration of our routers or workstations is not an option.
I have used ethereal and wireshark before. Ethereal may be a viable option, but wireshark seems to provide lots of information, but no practical way to make use of it. how to set up the box to be a transparent device on the network that will allow internet bound traffic to flow (freely)?
Possible Duplicate:Forward SSH traffic through a middle machine.I am looking to get an interactive ssh session on a remote machine, but must login via a gateway.For example, right now I do the following:
@local % ssh <user>@<gateway>
@gateway % ssh <user>@<remote>
Is it possible to achieve the same thing in a single command from my local machine? I have tried:
@local % ssh <user>@<gateway> 'ssh <user>@<remote>`
From the output i am indeed able to login, but do not get an interactive session. I took inspiration for this attempt from using ssh to run a command remotely.
In interactive mode (in Octave, gnuplot, R, etc.) I occasionally press Control + z by mistake. This pauses the program and kicks me back to the terminal.Is it possible to re-enter the original interactive mode (with all the stored variables)?
To reproduce:
~> octave
octave:1> a = [1:10];
octave:2> ^Z
[code].....
How can I recover my session with the variable a defined?
How can I disable the interactive boot up process? Also what is the pros and cons to doing this? Will this affect my being able to get to runlevel 1?
I have been googling it but not really clear on the pros/cons etc.
I am talking about a server class machine that is in a locked room, not a desktop.
I know it can be turned off in /etc/sysconfig/init # Set to anything other than 'no' to allow hotkey interactive startup... PROMPT=yes