Fedora Security :: How To Filter Ports
Apr 28, 2011I have open ports on my computer for vsftpd, pptpd, and I need help to filter this ports because they aper as open ports on internet, and this is pretty risky
View 3 RepliesI have open ports on my computer for vsftpd, pptpd, and I need help to filter this ports because they aper as open ports on internet, and this is pretty risky
View 3 Replieshave 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?
View 14 Replies View RelatedI just discovered that my server is sending huge amount of data out at about 1Mbps. My immediate thought was the deluge bittorrent client, however it is supposedly not running (and a check confirmed its total active torrents was set to 0). I turned off the network and went in to Firestarter to set the outbound traffic to restrictive, turned on network again and no more data was sent. A look in Firestarter / Events showed a long list of random ports being used (see further down). How can I identify what program is sending all the data?
In Firestarter it doesn't really say much more than the port. Not sure if it is some misconfigured program or a malware/virus. I just got my ADSL connected a few days ago, and before that I used a mobile broadband (3G) as I just relocated. During the period I used the 3G the server might have been without firewall for a few days and it was also at this time I discovered an increase in network traffic (but I didn't really pay much attention at that time). I am running Fedora 10.
List of events from firestarter, my server is 192.168.1.100:
Time:Jun 1 16:48:12 Direction: Outbound In: Out:eth1 Port:39435 Source:192.168.1.100 Destination:58.208.xxx.56 Length:129 TOS:0x00 Protocol:UDP Service:Unknown
Time:Jun 1 16:48:12 Direction: Outbound In: Out:eth1 Port:6990 Source:192.168.1.100 Destination:112.94.xxx.212 Length:129 TOS:0x00 Protocol:UDP Service:Unknown
Time:Jun 1 16:48:12 Direction: Outbound In: Out:eth1 Port:2973 Source:192.168.1.100 Destination:118.93.42.xxx Length:129 TOS:0x00 Protocol:UDP Service:Svnetworks .....
Tried google and searching this forum to no avail. Under Fedora 14, there is an selinux policy which blocks sshd from making outbound connections on port 80 or 443. This can occur when a client box tries to tunnel through the ssh connection for encrypted access to the web.
While I did manage to allow this happen by creating a permissive domain for sshd with this command:
Code:
The preferred way would be to allow sshd to make connection on other ports with a similar command that does not seem to work:
Code:
Is this the correct way of allowing an outbound port connection for the sshd daemon?
We operate a small ISP and are currently using a debian distro as our gateway server.Recently we have had an increased number of spam issues with customers (not them sending it directly, rather the customer getting infected with a virus/malware and then their computer becoming a bot).I'd like to set up another gateway of sorts to sit after our authentication gateway but before our backbone to provide spam filtering (and hopefully virus filtering) for any traffic passing through which might be email.I've tried searching for any linux based software which would suit, but I'm coming up empty.
Surely there's something already out there which can perform this task.Finally, just to clarify, I'm not talking about spam filtering for email accounts we host ourselves (this is built into our mail server); I'm talking about spam originating from customers PC's which is passing through our gateway (but not our mail server).
What is a good IP filter/firewall program? Seeing as how I like free softwares, I download a lot of torrents. When I was using Windows, I used PeerBlock (the newer fork of PeerGuardian), however, it's not available for Linux. What would be a good alternative for this in Linux? I tried iplist as it has a GUI, and it was extremely buggy and blocked random web pages even after I put them on the exceptions list. And MoBlock has no GUI from I understand, nor has it been updated in years.
View 9 Replies View RelatedWe have approximately 100 retail locations that will have split vpn tunneling. Intranet traffic will flow over the vpn to the corporate headquarters, voip traffic will tunnel to a regional hub and internet bound traffic will go over the local isp. The retail locations are small with 1-8 users and no enterprise grade equipment (servers, etc). This setup in effect will render our current content filtering solution useless.
The locations will be equipped with Cisco ASA 5505 Firewalls. The original plan was to use a Websense server and the url filtering feature to act as a content filter. I just found out that pricing for Websense was not included in the budget will be a show stopper.There may also be some performance issues with this method. Putting a proxy server at each location is not really an option. We do not have the resources to place a server at each location, plus the users could simply unplug an inline device or go around it. There is minimal supervision at most of these locations.
Ideally, I would like to find a way to use something like Dansguardian with an ldap interface and the url filtering feature of the ASA firewalls. I found a program called n2h2p, but I can find 0 documentation for it. It is also 2 years old with no updates. I also need to be able totrally manage this as trying to keep up with 100 different configurations for 400 users would be virtually impossible for the amount of time I will have available
Does anyone know the iptables statement that will block inbound SMTP messages that are NOT S/MIME encrypted?
View 1 Replies View RelatedI have been assigned a task to implement a free open source content filter having feature of web, email, instant messaging etc. If any one has the information or worked on this type of product please share it.
View 8 Replies View RelatedHow to filter condition based on full hostname? ie. allow inbound packets to port 25 if the packet comes from [URl]..
View 1 Replies View Relatedso how can I locate a printer behind a firewall? Is it possible to enumerate the subnet behind a router ( even if a connection has not been marked)?
View 3 Replies View RelatedI have a batch job which logs in to the server every 10 minutes via windows rsh. The job checks to see is there are any files that need to be send via a EDI serverto a supplier.The following logwatch report is swamped with the login messages and would like to either suppress the logging in PAM? or suppress the entry in the logwatch report?But I still want logging id the username is not username1.Connections (secure-log) Begin rshd[1754]: pam_rhosts_auth(rsh:auth): allowed to username1@10.0.0.1 as myedi
View 2 Replies View RelatedI followed this How To (https://help.ubuntu.com/community/Postfix) in order to add smtp authentication to my Postfix installation used as spam filter for my exhange server, and it'seem all ok; the only thing that I don't understand is where I list all the users (with passwords) that I authorize to send mail through my server...
View 3 Replies View RelatedHow can I tell if my USB ports are 2.0 ports?
View 1 Replies View RelatedIs there anyway i can ssh/rdp/telnet into my server from the outside bypassing comcast ALL blocked ports
View 1 Replies View RelatedAfter 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.
[Code]...
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.
View 4 Replies View RelatedWe 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.
View 4 Replies View Relatedlooking 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
View 4 Replies View RelatedI enabled ufw yesterday, and am finding log entries like:
Jun 30 13:07:51 xxxx kernel: [15702368.296557] [UFW BLOCK] IN=eth1 OUT= MAC=00:22:19:5e:8f:23:00:0c:db:fc:8b:00:08:00 SRC=xx.xx.xx.xx DST=xx.xx.xx.xx LEN=40 TOS=0x00 PREC=0x00 TTL=55 ID=47632 PROTO=TCP SPT=58875 DPT=80 WINDOW=65535 RES=0x00 ACK FIN URGP=0
What is puzzling is I did the command: ufw allow 80.
I installed Ubuntu 9.10 recently. I heard that there will be no open ports in the system unless I specifically open one. How do I scan to find a open port in my system.
View 9 Replies View Relatedwhen 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
[Code].....
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:
Code:
$ sudo iptables -F
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,
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View 2 Replies View RelatedWhat ports does Firefox use to connect to the Internet?
View 9 Replies View Relatedmy 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?
View 6 Replies View RelatedWhat are the security implications of closed ports?
View 5 Replies View RelatedWhat is happening when I log in to my Ubuntu server machine via ssh and putty. trying to understand everything, primarily securing my server.
I have specified the ssh server to listen on port 5525, and can login without a problem.
When I look at the logs though it says I connected from xxx.xx.xx.xx on port 53602.
What is happening here and why is the logged connection a different port to the one specified in the config file?
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A year ago I blogged about how hackers managed to hijack hundreds of high-profile websites to make them promote online stores that sold pirated software at about 5-10% of a real cost. They used quite a standard scheme that involved cloaking (making spammy links visible only to search engine crawlers) and conditional redirects (visitors from search engines who clicked on specifically-crafted links on compromised sites got redirected to online stores of software pirates)
Despite of all my warnings, most of those site are still hacked and help sell pirated software and steal credit card numbers. This negligence of site/server administrators encouraged cyber criminals to step even further in abusing reputation and resources of compromised servers. This post will be about one of such steps.