Ubuntu Security :: Cannot Connect To Port Number / When Firewall Is Enabled
Sep 5, 2010
i am using 9.10 karmic. Firewall is enabled. added ports with ufw allow [portnumber], and i still cannot connect to a port number. iv tryed ufw allow ssh/tcp but that does not work. the ports work when i disable the firewall and i dont want to do that.
ufw is available in all new installations of Ubuntu since 8.04 LTS, but is disabled by default. The standard Ubuntu installation has a no open service ports policy, so enabling the firewall by default doesn't gain any extra security in the default installation, but could provide confusion for people new to Ubuntu when new software that is installed does not work because of restrictive firewall rules. As a result, when first adding ufw to Ubuntu it was decided that users must 'opt-in' to using the firewall. In Ubuntu 9.04 and later, you can enable ufw during installation using preseeding. See /usr/share/doc/ufw/README.Debian for details.
I just installed Mandriva 2010 and set up the interactive firewall via the MLCC. I set it up not to allow any services to connect (didn't check any boxes). However, when I check my system using a port scanner (shields up at www.grc.com) it says that port 23 is open. Does anyone know why this would be and how I can close it When I look at the daemons running I notice that iptables and ip6tables are 'stopped' although shorewall is running - is this correct? I (perhaps wrongly) thought that iptables needed to be running in order for the firewall to work properly.
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
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
I'm not that great with mailservers, and just been thrown a curveball with a MS Exchange environment for which there is apparently no solution... yeah, right. But is there a workaround?
The problem is that the site mail (SMTP) needs to be sent via port 26 instead of the commonly used 25. Port 25 is mapped to a mailfilter, which apparently causes havoc with some of the mail, and the techs that have been on site trying to coax the Exchange server to co-operate have said that the only way would be to get rid of the filter.
The problem is that there are number of apps that are unable to have the outgoing port changed and so keep sending mail out on port 25.
I look after the Unix/Linux side of things at work, and I was wondering if there was an easy way to set up a Ubuntu box to receive mail on port 25 and just forward it to the MS box on port 26? So, in other words (and I hope this makes sense): monitor port 25, and forward whatever comes in on port 25 to the server on port 26. Simple portforwarding, or is it? What steps do I need to take?
If I forward port 80 to port 3128 for squid with an iptable rule, does port 3128 have to be open on the firewall or is this all routed behind the firewall?
I'm running Jaunty. For some reason, I cannot run Pogo games when the firewall is enabled. I've tried allowed "direct play gaming", thinking that might help, but it didn't. So i guess I need a custom protocol. What ports does Pogo use so I can allow them? Hopefully someone knows... and yes, I do have java. Pogo works if I turn the firewall off. Also, Ktorrent does not work either. I happen to know the ports this one uses, but when I make the protocol, it still doesn't allow torrents to run. The ports I'm trying are 6881 and UDP 4444.
2. PC with wired Internet connection + WIFI adapter OS: Windows XP Connection name and parameters same as above except ip: 192.168.1.40
I can see trial is getting connected with excellent strength. When i try to run an Internet on Ubuntu it is not working. Firewall is not active and Router is enabled.
When I enable my ufw it completely shuts me out and I have no internet connection. When I do:
Code: sudo ufw status numbered I get: Status: active
To Action From -- ------ ---- [ 1] 80 ALLOW IN Anywhere [ 2] 80 ALLOW OUT Anywhere (out)
But I need to disable my ufw in order to reconnect back to the internet. Why is that? Doesn't the above rules indicate that I should have inbound and outbound traffic even if my firewall is up?
Im a long time windows user and just installed Ubuntu 9.10 and have heard that i dont need any antivirus or spyware program on it, also is the firewall enabled by default if there is one and last thing do you need to do things like disk clean and defrag if so how.
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?
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.
The default Firewall ufw is not enabled by default at the time of installation and it has to be enabled by the user.Isn't this a security risk or is the user whether ufw is enabled or not secured from external threats?I am not much knowledgeable about network security But I am trying to understand the Ubuntu mentality behind this default setting.
OpenSSH_5.3p1 Debian-3ubuntu4, OpenSSL 0.9.8k 25 Mar 2009 debug1: Reading configuration data /etc/ssh/ssh_config debug1: Applying options for * debug1: Connecting to server ["address"] port 22. debug1: connect to address "address" port 22: Connection timed out ssh: connect to host "server" port 22: Connection timed out
I suppose this is because I am connecting from a public institute where there is a firewall that is blocking an outbound connection on port 22.Is there anyway I can bypass the firewall using the internet ?
sudo ssh -L 750:192.168.123.103:873 username@192.168.123.103It does exactly what it's supposed to do, but how do i edit / remove this rule?Is there some config file where i can alter the forwarding? How does it get stored?Im using Ubuntu 10.10Server Edition (allthough i recon it would be pretty much the same across all versions
Is there any way to verify if packets being trafficked over a certain port are valid for the service you want to use this port for?
One obvious example that probably clarifies my question: When I open port 443 (outgoing or incoming) for https/ssl traffic, I don't want this port to be used for say openvpn traffic. Thus: when someone wants to surf to a website with https, it should be ok but if someone wants to connect to his home openvpn server over that same port, it should be blocked.
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 would like to change port number for a specific folder name on linux server like domain.com/folder_name:yyyy so people can access that folder with pre defined port number. is there a way that I can do that?
I'll explain this in one sentence: Is it possible to program a port-binding shellcode in which people across the Internet can connect to, without being thwarted by the router blocking their data because the port its bound to doesn't allow port-forwarding
i have to deal with reverse proxy issue and want to access few LAN devices having port 5900 and 9999, what exact steps i have to follow to allow this port in fedora firewall.
I have a problem sending of file attachment using Instant Messengeri have a firewall using firestarter, if i used outside firewall they can able to recieve my file in instant meesenger but if i used firestarter it always cancelled my sending of file attachment....
I want to open port 2700 on my firewall but I don't know how I try with Code:iptables -A INPUT -i eth0 -p tcp --sport 2700 -m state --state ESTABLISHED -j ACCEPT But the port is not open I see the firewall configuration with the command setup . I use CentOS 5.3 here a screen of my configuration :http://upbg.net/out.php/i3537_sshot3.pngCurrently my firewall is off because I don't know how to turn on 2700 when the port is open I will turn on firewall .If I write 2700 in other ports field will 2700 be open ? Before 1 month I try but the port was not open . I have only 1 last question will firewall reduce the load of the my server now mysql use many CPU % and I just don't know why
im using CentOS 5.2 and cant change my default ssh port number. I have edited /etc/ssh/sshd_config to this
Code:
#$OpenBSD: ssh_config,v 1.21 2005/12/06 22:38:27 reyk Exp $ # This is the ssh client system-wide configuration file. See # ssh_config(5) for more information. This file provides defaults for # users, and the values can be changed in per-user configuration files
[code]....
I have then restarted ssh by typing (as root) "sbin/service sshd restart" and it restarts fine but still is on 22 and not 222.
i have installed CentOS along with ISPConfig. For some reason apache will not run it says there are no listening sockets avaliable. I have done a netstat and also tried nmap to see if any other service was using port 80 but it doesnt show anything. I also tried changing the port number to something like 81 still no go. On bootup of CentOS it shows the error and a message saying unable to open logs.
