Ubuntu Security :: Firewall "blocked" IP But Still Connecting?
Jul 27, 2011
I was using Transmission BitTorrent the other night, when I noticed that I was getting heavily spammed by one particular IP. I then stopped the torrents and disabled the network.I wanted to add my own block-list, containing this IP, to $HOME/.config/transmission/blocklists, but could not get it working. Transmission is supposed to parse this text file into binary format upon startup. I tried both allowed formats, but Transmission kept on creating an empty binary file (this was version 1.93 in the official repo, I have since upgraded to 2.33 by adding a PPA, and it now works correctly).
I then blocked this IP in the firewall outbound traffic policy, allowing Transmission, on the port number that I forwarded on the router, on the inbound policy. After a restart, I watched the torrents picking up speed as more peers connected, and then saw this IP getting blocked. However, the same IP immediately also appeared as a peer in one of my torrents.I then double checked all settings and log files, to ensure that there is no typo. The same IP that was shown as blocked in the log files, also successfully made a connection to Transmission. After a while I gave up, and shut down.The IP was an incoming connection, but was explicitly nominated to be blocked in outgoing traffic. The firewall was supposed to silently ignore this IP, not making a connection possible.
ICMP filtering was enabled, with the following not allowed:
If I use my current iptables firewall settings my php includes from my own site get blocked by the firewall. If I use accept all tcp and udp it still does not work. If I use a default policy of accept all, then the php includes work which is not safe. I am running a drupal 6 site on a centos 5.3 vps with apache 2.2.0 and php 5.2.6 w/ safe mode on. He is my current iptable configuration.
I run ubuntu on home pc and am very happy with it. I use internet to surf and to see my email on gmail.com etc. What commands should I give to setup ufw firewall so that only this much is allowed? Also, where can I see if some other connections have been blocked?
The firewall in Fedora 12 seems to block UPnP by default, but opening port 1900 for UDP, as I have seen suggestedes not resolve the problem.have the following three scenarios:Firewall Enabled: Transmission cannot open a port by UPnPFirewall Enabled (1900 UDP allowed): Transmission cannot open a port by UPnPFirewall Disabled: Transmission opens a port via UPnP fineAny ideas? Yes, the port that I'm trying to open is also allowed. Router is a Linksys BEFSR41 v4.3, should you care
i have a server running vsftpd, and when i connect to it from the server itself using my externel ip address, everything checks ok, and i can browse files. but when i try to do the same on a windows computer on my network, this is what happens: [my externel ip is blocked out with x]
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now mind you, my linux server is running from port forwarding from my router, which is connected to the main computer, and i have ssh and squid running as well. not sure if those two have any affect on the service. i think this is a problem with the firewall, because i have read somewhere that multiple ports need to be open for a passive ftp to work.
I setup Mediatomb on another box in my house to connect to with XBMC. XBMC will only connect though if the firewall is off on the local machine. I have both TCP and UCP ports 1900 and 50500 (the port for Mediatomb) enabled on my laptop (local) and the correct ports are open on the remote machine (my wife's vista laptop will connect through XBMC). I can connect to Mediatomb through it's web interface (to set visible folders/files) but not through UPnP (at least not through XBMC)
Small server running 5.3 - stock postfix configured to use Maildir. Dovecot configured but both pop and imap ports blocked by firewall. Access to mail is via Squirrelmail via https. Configured to virus scan via ClamAV. Works just fine. Now I want to add procmail filtering. So I create these two files - ~/.forward and ~/.procmailrc in my user home dir: "|exec /usr/bin/procmail -f- || exit 75 #mpeters"
I've setup the Uncomplicated Firewall (UFW) on Ubuntu 10.04 LTS and blocked an IP address. UFW status shows that the firewall is active and the IP in question is denied. The issue is that I'm seeing the blocked IP address in my Apache logs.
We have a spam in our network and we installed antivirus in all our systems and cleaned the virus from all pc's after that i had removed my ip from the database of blocked ip's but still my ip is blocked for sending spam i don't know from which pc the spam is going on the internet.
so i have a question that my proxy server is redhat linux and as a newbie i don't know the command's to find out which pc is creating large bandwidth to the internet. If you tell the command how to see which pc is sending spam then i will discard that pc. Also i want a strong firewall to stop spam activities.
I have installed MoBlock as instructed here: [URL]
After installation I created my own list file in /etc/blockcontrol/custom-blocklist.p2p and have the following uncommented at the bottom of /etc/blockcontrol/blocklists.list:
Code: Yahoo:98.137.149.56 Google:74.125.47.147 When I do:
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Recently I just noticed that the locallist rules seem to have no effect. I will always get "destination port unreachable" even if the locallist entry in blocklists.list is commented out.
However, whenever I try to browse to that IP, even when blockcontrol is on, even by typing the IP into Konqueror (not the domain name), it lets me go there every time. How can I know that my other applications will not to do the same thing? How can I lock this down and test it empirically to be sure?
On April 10, 2010, I upgraded some packages on my Ubuntu 9.04 server. This included an upgrade to "ufw 0.27-0ubuntu2". I rebooted the server, and all appeared to be fine.
Now I've noticed that UFW is not logging blocked packets since that reboot. It used to do this. It is still logging the allowed packets that I've configured it to log.
I come to Ubuntu with the notion that it is much more secure than Windows. In XP I had an anti-virus, third-party firewall and sundry softwares against spybots, rootkits etc. The anitivirus blocked the suspicious web pages while browsing. I generally avoided public networks, carrying a portable internet device Do I need similar stuff with Ubuntu.
I don't know is this the right place to ask, but i must ask some questions Here's my problem.I'm a student in highscool,and here we use Linux(ubuntu) OS .Every classroom has like 30 PC's connected with the main computer(the teacher's one) so....3 days ago we were forbidden access to some websites it says This domain is Blocked.By the way the Linux version installed is 7.04(feisty Fawn) i tried disable cookies that did not worked,also tried to whitelist some website,that also didn't worked out
I have squid as a proxy on the Suse box, and with the default firewall I have to enable masquerading to allow clients on the eth3:1-3 to send and receive mail through the Suse box. I found the Suse firewall completely inadequate (all P2P software/connections are allowed once you enable masquerading) and had to install ConfigServer Security & Firewall. In die configuration of csf I could get my way around getting smtp to work for the eth3:1-3 clients, but pop3 connections does not go through the box. I know I need to allow port 110 and 995 to masquerade of NAT (or something) and then the same for port 22
I have Ubuntu running on an old PE server. It is running Virtualbox with an instance of Ubuntu inside. The instance is there to run my honeypot.
The server box IP is192.168.1.10. The Virtualbox is bridged with it's own IP of 192.168.1.200. The honeypot daemon is listening to 192.168.1.201 with arpd.
I set up the UFW with DENY. And then enabled only the ports leading to the honeypot scripts which are abound to IP .201. I then forwarded the ports necessary to run VNC to .200.
Here is the UFW status: buntu@ubuntu-desktop:/var/lib$ sudo ufw status Status: active To Action From -- ------ ---- 192.168.1.201 21/tcp ALLOW 21/tcp 192.168.1.201 4444/tcp ALLOW 4444/tcp 192.168.1.201 5544/tcp ALLOW 5544/tcp
In the past week or so I've noticed some weird network behaviour. I find accessing some sites such as Amazon, Paypal, and Bigstockphoto really slow. Sometimes the page will not load at all. Other sites are fine. The problem sites are not a problem for others on my LAN at home. When I try to open the problem sites, I can see in Firestarter blocked connections coming from 2.1(8/9).xxx.xxx on various ports such as 36007. This only happens for the problem sites. I attached a typical output from firestarter.
This happens with Firfeox or Chrome. Using Ubuntu 10.10
I have a VPS (Ubuntu 8.04 server eition) and as such am stuck with using a software firewall.
i currently have UFW installed.
I would ideally like to have my firewall be a little rude, or rather just not polite. I know what i am asking will break the RFC, but i consider this ok due to the security benefits.
I would like to have my firewall 1) ignore (eg drop without responding)all packets that dont start with a syn flag 2)for all other traffic that is currently blocked, have it dropped (again drop it without responding)
If there are any other rules you can think of i would like to know them. I already have only the services i want open and the rest blocked.
I've been using Windows for quite a few years now. I loved the way how I used to set incoming/outgoing rules for my applications. But I'm having hard time doing that in Ubuntu. I tried searching for a good GUI for iptables but I need your help selecting the best. I might learn iptables someday but for the time being I will be using a nice GUI. I'm currently using GUFW, I've tried Firestarter. All I need is a firewall that would allow me to configure rules for my applications.
I have set up a Ubuntu 10.10 server. I have been using ssh tunnels to encrypt my web traffic at public wifi. I am trying to make this server as secure as posible so I enabled ufw. I allowed SSH and HTTP traffic in and denied everything else. But when I do that I can not use SSH -D because when I try to visit a webpage it does not load and I get the following.
Code: uname@mybox:~$ channel 3: open failed: connect failed: Connection timed out ^C uname@mybox:~$ fclchannel 4: open failed: connect failed: Connection timed out ^C uname@mybox:~$ exit logout
What do I have to do to allow ufw to allow ssh tunnels through?
I am a Linux newbie so please bear with me if I sound stupid. I was checking out how to set up a firewall for my system and landed on this webpage: [URL]. But I am so confused with how this ufw application works. What I understand is that once I set it to "default deny" it prevents unauthorized incoming connection but what does it mean when the author says to add exceptions for services I need? When do I need to do that? Also what's an SSH server?
I'm involved in a project to students set up a network security training lab using vmware. I want to simulate (in a very rough way) scanning through a poorly configured router or firewall. The easiest way I can think of to simulate this is to use a linux vmware image with two virtual nic cards to act as a firewall with the attacker on the outside network and a domain controller, web server, and database server on the inside network.
I would like to start students off with a firewall script that exposes everything on their internal network to the attacker. Is there an easy way to (mis)configure iptables to do this?. The model I'm trying to replicate is something like this. Attackers were on a 10.10.x.x network, defenders were on a 192.168.x.x network. As an attacker I could nmap 192.168.x.x and see every machine and every service on the defenders side even if they moved a service to an unexpected location. how I can implement a similar configuration using a linux image as firewalls/routers in vmware?
I have a set of iptables rules generated by Firestarter, and i'm in the process of trying to familiarise myself with iptables itself, but there's one particular rule which is confusing me, perhaps somebody could explain it to me
I'm running the firestarter firewall and its been showing the odd ssh attempt quite often. e.g. I've had 4 attempts today, 3 in the last 40mins. I realize that this may be nothing to serious but it's got me curious, aside from having a secure password (which I have) is there anything that else that I can do to ensure that my system is as secure as possible from ssh? I do use ssh within my home network so I don't want to disable it completely.
