Security :: Anyway To NOT Log Dropped Ports 137 / 138 In Iptables?
Mar 30, 2011
We do NOT support samba on our Unbuntu servers but still zillions of windows machines are constantly trying to connect on the SMB ports. I've added a rule that drops access to destination ports 137-138 and that seems to work. But it creates many many log entries documenting that the packet has been dropped. I've been researching and cannot come up with a way to suppress logging for these drops.
I am running a server with ssh and a vpn server set up. It is behind a debian router with a firewall which uses iptables. i have it set up to forward ports 22 and 443 to ssh on a computer within the LAN(so when on a restricted network i can still ssh into my network) and forward anything to 1723(for my vpn) to that box also. However, the only port that gets successfully forwarded is port 22. The other two appear closed. here is what the script looks like:
I am trying to figure out what command to use to show the number of DROPPED and INVALID packets that the firewall is handling.I'm going to put these commands into a log analyzer script which will run every 15 minutes with cron. The firewall is running and operating the way I want it to. I'm running CentOS 5.4.
I want to portforward client connections from an ubuntu lts server to another external server. btw i am a noob on iptables. i have tryed using the basic commands for iptables with no success. For example:iptables -A PREROUTING -t nat -i eth1 -p tcp --dport 7878 -j DNAT --to 22.214.171.124:7878iptables -A FORWARD -p tcp -i eth1 -o eth0 -d 126.96.36.199 --dport 7878 -j ACCEPTso basically i just want a rediraction for from one ip to another. Example: A client tries to connect to ip 188.8.131.52 on port 7878 and the server forwards him to ip xx.xx.xx.xx on port 7878, meaning that xx.xx.xx.xx is the actual server with services. Server with ip 184.108.40.206 is only forwarding the client to external ip... how can this be done in a simple command?
I am trying to open VNC ports(5901,5902) on my RHLinux machine using iptables. I am able to do it from GUI system-config-security. Go to the Administration > Security Level and Firewall, then select "other ports" at the bottom and enter the portNum 5901 to open and select tcp, then click OK and OK again to save your settings. From my windows m/n iam able to open vncsession using vncviewer on 5901 port.But when I am trying to do it from command line:#iptables -A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 5901 -j ACCEPTThis command added the entry in /etc/sysconfig/iptables and listed in iptables -L command.Then I saved and restarted the iptables.#service iptables save #service iptables restartWhen I am trying to open the VNC session from vncviewer, it is giving me error and session not opened.Is there some thing I missed here? where can I check the logs for this? I definetly need
I have a Suse 10.3 router with 4 network cards. 1 is to connect to the big network and thereby also the internet, 2 are for 'client' subnets and I want to use the last one as a DMZ. In this DMZ will be a web server which has to be accessible from the other 2 subnets and from the big network. I could do it with a few simple clicks in Yast firewall, but I have some issues with this firewall and there for I want to use it as minimal as possible, using Iptables.
So now I'm struggling a bit with Iptables. Basicly what I'm looking for is how to block all ports but 80 in this last subnet with iptables.
Because my ISP is blocking every IP port under 1000, I'd like my local nat'ed server to be able to translate incoming and outgoing traffic from some port above 1000 to the default server port locally.Example :
To connect to my IMAP server (default port : 143) from the outside,I'd connect to my public IP, port 1143 (opened and nat'ed to the right server on my router) and the server would translate this port to 143 on the same machine.I wish I could simply configure my router to do that but sadly Linksys doesn't permit such setting... I also could modify the listening port of my server but I prefear to keep the default port inside my network.I think that iptables is the right tool to do that and I never used it and I must say that this tool is not so easy to configure at first sigh
I'm having some issues settings up a transparent proxy server, which should allow only regular web browsing (port 80), any other port (including HTTPS (443)) has to be blocked, as well as any other port. Right now, I'm using Debian 6 and Squid3. The server only has one NIC. The topology is like this: Clients <-> Proxy Server + DHCP Server <-> Internet
With this setup, the network does have internet access and the websites I whitelisted are the only ones accesible via browser, however port block is not working, every port is open, hence why trying to access blacklisted websites through HTTPS is possible. Seems to me Squid3 is doing it's job fine, however IPTABLES for some reason seems to be redirecting all the trafic to port 3128 (Squid3 port). I could be wrong, but I've been unable to do anything related to ports with squid3 (either whitelisting or blacklisting).
For Iptables I used: Code: iptables -A PREROUTING -t nat -i eth0 -p tcp -j REDIRECT --dport 80 --to-port 3128 iptables -A INPUT -i eth0 -m tcp -p tcp --dport 80 -j ACCEPT iptables -A INPUT -i eth0 -m tcp -p tcp --dport 22 -j ACCEPT iptables -A INPUT -i eth0 -m tcp -p tcp --dport 3128 -j ACCEPT iptables -A INPUT -i eth0 -m tcp -p tcp --dport 443 -j DROP
I am trying to edit the iptables to include some ports/ip for openfire server. The problem is the computer is very locked down with permissions...I logged in as ROOT with ID 0.Now the iptables has ROOT for permission BUT ID 1 which reflects BIN.As root i cant edit or chmod/chown the iptables. Here is what i tried:
1. change password of BIN - successfully changed with no errors BUT still cant su BIN with the new password...
2. tried changing the ID of ROOT to 1 but I dont have permission to use the command....
so anything i can do here??? I dont have permission with Shadow either...
I switched over to Fedora a couple of days ago. I'm using the built-in firewall shipped with it but I can't find out how to enable logging of dropped packets. Among others I'd like to use psad that needs firewall logging. Is there an easy way to do this? I'm not an iptables "expert".
After reading a lot about networking and security I decided to check the security of my own ubuntu box. So I went installing Nmap and discovered that port 139 was "open". Since I 'd read how to use ufw I created a deny rule for port 139. After a second scan with Nmap it still said that port 139 was open as shown below.
I'm locking down my laptop. I know I can use a firewall to ensure nothing gets through that I didn't catch, and I certainly plan on using one, but in the meantime, I want to know what exactly is running on my system.
nmap localhost returns: Code: james@james-linux:~$ nmap localhost Starting Nmap 5.00 ( http://nmap.org ) at 2010-07-26 23:33 CDT Warning: Hostname localhost resolves to 2 IPs. Using 127.0.0.1. Interesting ports on localhost (127.0.0.1): Not shown: 994 closed ports PORT STATE SERVICE 25/tcp open smtp 111/tcp open rpcbind 139/tcp open netbios-ssn 445/tcp open microsoft-ds 631/tcp open ipp 2049/tcp open nfs Nmap done: 1 IP address (1 host up) scanned in 0.18 seconds
However, I know that localhost goes back to the loopback interface, 127.0.0.1. So, to see what was really open, I ran nmap 192.168.0.108, which is my laptop's IP at the moment.
Code: james@james-linux:~$ nmap 192.168.0.108 Starting Nmap 5.00 ( http://nmap.org ) at 2010-07-26 23:33 CDT Interesting ports on 192.168.0.108: Not shown: 996 closed ports PORT STATE SERVICE 111/tcp open rpcbind 139/tcp open netbios-ssn 445/tcp open microsoft-ds 2049/tcp open nfs Nmap done: 1 IP address (1 host up) scanned in 0.14 seconds
Now if I understand correctly, I can attribute 139 and 445 to my Samba share. That I'm okay with. What I don't know is 111 and 2049. Does anyone know what these ports are, what's running on them, and how I could turn them off, supposing that they are a security risk?
I'm getting heat from the head networking office that ports 21, 110, and 143 are open. I can telnet to those ports from a remote machine (not localhost) and get a prompt. There does not seem to be anything listening on those ports according to netstat. I've tried using iptables to discard all traffic to a from those ports but I can still telnet to them. This is a lucid desktop machine.
looking at my router logs i've noticed for the past while a range of source ports from 60000 to about 65000 from my source external ip to destination external ip always on port 80. I have 3 boxes on this network and this only seems to happen when i connect the one laptop. I even reinstalled the distro downloaded from trusted source but the router is still logging this.. netstat -ntulp shows nothing operating in this range. chkrootkit shows nothing.. Was thinking maybe someone was spoofing the external address but it's been happening on network startup for a month now
have tried to close ports 443,80,22 & 23 without success.Does anybody have any idea how to do this. I close them in a terminal and their still opened. I closed them in services and their still open what am I not doing right?
when i enable my ufw it completely shuts me out and closed my internet connection. i installed firewall configuraiton interface and through it defined rules to accept incoming internet connections on port 80, i can see the rules are there but when i enable my firewall it just shuts me out completely again. when i do(with my firewall enabled):
Code: $ sudo ufw status it gives me: Quote: Status: active
I also messed around with fwbuilder and iptables but since then deleted fwbuilder(besides i just compiled firewall policy and never actually installed it because of errors while trying to install it. Iptables I cleared with:
I know how to forward ports in my router. Now I need to open a port to help with testing a project and no matter what I've tried, every port under 1055 shows up as stealthed (with 1-71 closed) according to Shields Up! I'm happy to run it at a port > 1024, but whatever I try also shows up stealthed. I even tried (briefly) turning on DMZ and still the same thing. My ISP swears that they only block port 80, 21 and 25, none of which I'm trying to use. UFW status reports inactive and I'm not using firestarter. I'm not running any other server (apache, light speed etc). If it's not my router and it's not my ISP, and there's no other server apps running, then that kind of leaves Ubuntu as far as I can see,