Security :: Getting The Connections To IRC Server?
Feb 4, 2010
For some time now I've been noticing the network activity light for my linux box blinking like mad on my router. After a little looking around for ways to see what connections my box has established, I found the following using lsof -i
I know I'm not using IRC, and I have my sshd locked down fairly tight, requiring a key to log in, so obviously, it looks like there's something or somebody in Croatia (the origin of that IP address) connecting my system to undernet.org for some nefarious purpose. Looking at my processes, ID 13839 shows up as
Code:
13839 ? S 0:00 bash
Just 'bash', not '-bash' as
Code:
13426 pts/0 S 0:00 -bash
my session appears. Previously, this odd bash process was ID 2704, which seemed to imply that it had launched fairly soon after my system booted up which really makes me wonder. Oh, and yes, I did kill that 2704 process, and it returned as this 13839. 2704 also had those same IRC connections present in lsof.
Is it fair to say that connLimit and hashlimit are very similiar on Linux i.e. while hashlimit caters to limits for groups of ports, they both set the connection rate limit per host? How in IPTables, do I configure a policy that limits connections on a port that encapsulates the total sum of all connections from all hosts? i.e. I do not want to allow more than 6000conn/minute for port range that is the sum of all connecting hosts?
On my server I some times login from my home where I have an internet connection which does not have a static IP each time I switch on my modem a dynamic IP isgenerated.I see in auth.log logs of following lines Quote:reverse mapping checking getaddrinfo forkkts-kk-dynamic-01.1.168.192.some_broadband.in [192.168.1.2] failed - POSSIBLE BREAK-IN ATTEMPT Accepted publickey for root from 192.168.1.2 port 22852 ssh2when ever I login to my server from home.In this case I do know that it was me who logged in but still why do I see such a log.What is this complaining about?
have a problem with my network-manager in ubuntu 10.10.when I dial one of my vpn connections, my other vpn connections be disabled and I can't use them!I tried to restart network-manager and gnome-panel, but it does't seem to solve this problem.
on my linux server i have many websites but with difrent ips address, is some way to i can block all the ips with many connection (100+) just from my website not from all websites
Its been really bugging me that whenever I scan my connection with wireshark I see this one person sending me a SYN packet every minute on port 445. I know this is the dangerous port that the Conficker worm travels along. So far my computer seems to be immune and I know, at least on the Linux side that I can just add a rule to my ip tables to block that port indefinitely. I want to know what the next step is.
This is one of the packet captures I am getting. After sending me this and getting no reply, all of a sudden he goes up an ip. Basically this would be the pseudocode for what it looks like hes doing on my end.
while(1){ for(int i = 1; i != 255; i++){ send_connection_attempt("XX.XX.XX." + i); } }
To me this looks like this guy has hijacked a computer and is using it to run a script over. He is still scanning my network as I said earlier, what should I do? Should I contact my ISP? or just nail down the hatches and make sure nothing is exposed on my network?
I checked all the logs in /var/log but couldn't see anything (I was hoping /var/log/auth.log would have it, just like it has ssh connections in there). I've got a machine that several people VNC into and I would like to keep track of things. Are there other VNC servers out there that keep logs? I could switch, but I went with krfb because it works perfectly for me and came already installed.
I might be misunderstanding the log but it looks like UFW is blocking connections. I want to allow all incoming and outgoing. I guess what I'm saying is that the servers on my computer will open ports but all other ports should respond with closed just like a default Ubuntu install. Trying to use UFW to monitor connections without really doing any firewalling.
I need to limit the number of ssh connections a user has. All the users are using tunnel only so their shell is set to /sbin/nologin The logins do not open a shell they just create the tunnel so /etc/security/limits.conf has no effect on them at all.
I tried setting 'MaxSessions 1' in sshd_config but either that doesn't not do what I expect it to or it plain does not work as even with a normal user I was able to open an unlimited number of sessions. I need a good secure way to limit each user to 1 ssh session without them having a shell but Im unable to find a solution.
I have noticed interesting problem. I use two browsers - Firefox and Konqueror. Konqueror is configured to use tor, Firefox not. Using Gufw I block all incoming and outgoing traffic and it works while using Firefox, I mean that I can't view any www site and it is ok. But if I use Konqueror I can establish any conection. How to understand this? Should I have different firewall while using tor?
I know that GNU/Linux does not need a firewall (due to iptables), but I would like a basic firewall that would watch incoming and outgoing connections. I would prefer it to have a try icon and be able to run as a regular user, such that I can add it to my .fluxbox/startup file. Anyone know of any good ones? They don't actually have to interface into iptables (because I would do that myself), but if they do it would be a bonus.
I am running Ubuntu 10.10 I have an question about the firewall Firestarter, when checking the firewall it told me there are 9 serious incoming connections what must I do with this info. Inbound is normally blocked as standard i have also see that someone with port 1234 and 12345 have trying to attempt mine system but failed all trojan ports are fully blocked.
I have tried to configure my iptables to allow only HTTPS connections to the internet. Unfortunately, I didn't get that to work. I configured it like this:
Quote:
iptables -P INPUT DROP iptables -P OUTPUT DROP iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT iptables -A OUTPUT -t filter -p tcp --dport 53 -j ACCEPT iptables -A OUTPUT -t filter -p udp --dport 53 -j ACCEPT
[Code]....
Of course I am only trying to access websites via HTTPS Still, I was wondering if HTTPS somehow under the hood requires the HTTP port to be open or if my rules are in some other way wrong.
I am running Firestarter on Ubuntu 9.10 64 bit. I have noticed several times that after closing all web apps (Firefox, Thunderbird) that some entries remain under the heading "Active connections" on the Firestarter "Status" tab. Often these show no source program. Currently I have 2 showing which show Firefox as the source. These persist after Firefox is shut down. I have verified that no Firfox process is running. And both of the IPs point to google.I have Disconnected eht0 and they still show. I have logged out and back in and they still show. I must reboot the machine to make these entries go away. Which makes me think perhaps this is a bug in Firestarter(?) Is there another way I can identify truly active connections?
if i want user should`t have more than 20 sftp connections to a server,is there any way we can limit no.of connections to a particular user on the server using ssh configuration
Mobloquer starts up at boot and before I've even opened firefox or transmission or anything, mobloquer shows that is has started blocking several outgoing connections as well as ton of incoming connections. I was wondering if the outgoing connections is normal and what's a normal amount of network activity to show up in system monitor when I'm not actively using the internet.
my ufw rules have been loaded and active yet using iptraf i see tcp connections on ports that were never allowed by ufw. can anyone explain this too me does ufw just not work?
I'm having problems with hackers from across the globe trying to get into our servers. Why? i have no clue. nothing of value in my servers worth getting.
Right now my service only does business with USA. So I'm trying to find a way to block all Non USA traffic. I called my hosting provider and they are unable to help. Said it was up to me to do this.
Well I've already taken care of the TCP Wrappers. by spawning a small C program i made that uses MaxMind's GeoIP system. to automatically deny access. Now i need to do something about all the other network connections that come in to services that do not use the TCP wrappers.
So i was wondering if IPTABLES have a way to spawn a sub proccess like TCP wrappers or if there was any other firewall software out there for linux that would let me achieve my goal.
How to number of connections for a single ip on port 80 to CentOS 5.5 with iptables? connlimit did not work on CentOS and nginx does not provide a module for that
We are trying to define an appliance based on Suse for an application server and Web server Apache, so we would like to know configuration best practices for network and security, is there any paper/doc about best practices?
I 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?
Can anyone walk me through the process of increasing my max connection on my linux server?Over the last few weeks I have been getting errors saying I have to many connections.I think the default is 100 and I would like to maybe increase it to 150 or 200I know I cannot go to high because I will then be using to much of my memory or maybe CPU
I recently installed Fedora 15 now, and during installation I set the internet connection manually, then did update and after reboot, the internet connection settings have been removed. Now I can not set because the network connection to the Internet Connection is inactive. I mention that before the update was functional internet connection.
Basically it looks like someone is flooding the UDP port for our server, which is running a game (Halo PC) through wine on Linux.I've tried "netstat -aun" but only get 0.0.0.0.'s as the IP address. there's anything I can install to log connections or any command I can run. Specifically they need to be UDP on port 2302 and port 2304- but since these Halo servers are the only thing running on this server, logging all connections would equally suffice.
Does a firewall exist, that shows "whois" info for ALL new connections that are attempted? Or even better, "smartwhois" info?New connections meaning, connections to IP blocks never connected to before. So you go to a site that belongs to owner A, and if an attempt is covertly made to connect to another site that belongs to owner B, an alert is shown and you choose if you trust this owner.
Is it possible to do limit the SSH connections using IPTABLES, like per day minimum 10 times only ssh connections can allow like that, or any other way to limit the SSH connections.
I have installed Debian Lenny 5 and am trying to access the server via SSH port 22 but it keeps telling me : Connection refused .Any ideas how to enable this SSH on Debian server for connections ???
Ok so, buddy of mine has his ssh server setup and upon checking his logs he sees a ton of failed attempts. Now obviously these are people that are scanning him and trying to brute force him. So is there a way to block them? We know you can block each IP but is there a way to block ALL connections except for certain ones, such as his and mine? Maybe a couple others.
