I am trying to force all my tun0's traffic through VPN but some some reason, the ufw is not working the way I want to.
Below are the commands that I have executed.. I am able to connect to my SSH and NFS server but for some reason that I am unable to understand, I am unable to surf the net.
What am I missing?
Hi everyone,
I have had trouble getting several versions of Linux stable on my machine over the last few months.
I do not think the issue is with the machine. Windows ran fine on it for a long time.
The current issue is that whenever I lock the screen then come back after a long time I find... (2 Replies)
Hi.
Yesterday I installed Solaris 11.3 and I tried to setup a VPN but I didn't find how to make it.
I saw the "network manager" where I found the ethernet connection but I didn't find where to add a VPN connection.
When I used Debian Linux there was NetworkManagerVPN that with a GUI I... (0 Replies)
Hi ,
In our ubuntu server 10.10 ,we are getting below logs .Every day i need to restart server ,other wise it will not accessible.Some times ,i need to restart two times.
When i ping google.com ,it was very slow .some times host not reachable .After reboot ,it will ping as good.
... (0 Replies)
Hi,
I have enabled my UBUNTU 9.10 ufw. By default does it let anything through?
I would think it allows all outbound originating requests through and allows for their return but it does not allow any inbound requests. Is this how it works?
---------- Post updated at 08:17 PM ----------... (1 Reply)
Hi,
I want to work on a remote unix server, then on a windows XP station I have a Forticlient that makes a VPN to the network on which the server is situated. But then I do not know how to work with. In DOS box (cmd BOX) I issue:
telnet myserver
but It does not know IT.
Any idea ?
Many thanks. (2 Replies)
Hi,
I have two unix networks connected via VPN via IPsec. I am using snapgear vpn devices at each location. The two devices can ping one another, as well as the unix network behind the respected devices. The unix machines can ping their local vpn devices. However, I am having issues pinging... (1 Reply)
We have an older model DG Aviion Unix system and we're trying to switch to VPN but we can't talk to the Unix box... can't ping or telnet to it, but we can talk to all our other systems (PC/NT servers).
Is there a network/tcpip setting we're missing? Something we have to change/set, either on... (0 Replies)
UFW FRAMEWORK(8) August 2009 UFW FRAMEWORK(8)NAME
ufw-framework - using the ufw framework
DESCRIPTION
ufw provides both a command line interface and a framework for managing a netfilter firewall. While the ufw command provides an easy to use
interface for managing a firewall, the ufw framework provides the administrator methods to customize default behavior and add rules not
supported by the command line tool. In this way, ufw can take full advantage of Linux netfilter's power and flexibility.
OVERVIEW
The framework provides boot time initialization, rules files for adding custom rules, a method for loading netfilter modules, configuration
of kernel parameters and configuration of IPv6. The framework consists of the following files:
/lib/ufw/ufw-init
initialization script
/etc/ufw/before[6].rules
rules file containing rules evaluated before UI added rules
/lib/ufw/user[6].rules
rules file containing UI added rules (managed with the ufw command)
/etc/ufw/after[6].rules
rules file containing rules evaluated after UI added rules
/etc/default/ufw
high level configuration
/etc/ufw/sysctl.conf
kernel network tunables
/etc/ufw/ufw.conf
additional high level configuration
BOOT INITIALIZATION
ufw is started on boot with /lib/ufw/ufw-init. This script is a standard SysV style initscript used by the ufw command and should not be
modified. It supports the following arguments:
start: loads the firewall
stop: unloads the firewall
restart:
reloads the firewall
force-reload:
same as restart
status:
basic status of the firewall
force-stop:
same as stop, except does not check if the firewall is already loaded
flush-all:
flushes the built-in chains, deletes all non-built-in chains and resets the policy to ACCEPT
ufw uses many user-defined chains in addition to the built-in iptables chains. If MANAGE_BUILTINS in /etc/default/ufw is set to 'yes', on
stop and reload the built-in chains are flushed. If it is set to 'no', on stop and reload the ufw secondary chains are removed and the ufw
primary chains are flushed. In addition to flushing the ufw specific chains, it keeps the primary chains in the same order with respect to
any other user-defined chains that may have been added. This allows for ufw to interoperate with other software that may manage their own
firewall rules.
To ensure your firewall is loading on boot, you must integrate this script into the boot process. Consult your distribution's documentation
for the proper way to modify your boot process if ufw is not already integrated.
RULES FILES
ufw is in part a front-end for iptables-restore, with its rules saved in /etc/ufw/before.rules, /etc/ufw/after.rules and
/lib/ufw/user.rules. Administrators can customize before.rules and after.rules as desired using the standard iptables-restore syntax.
Rules are evaluated as follows: before.rules first, user.rules next, and after.rules last. IPv6 rules are evaluated in the same way, with
the rules files named before6.rules, user6.rules and after6.rules. Please note that ufw status only shows rules added with ufw and not the
rules found in the /etc/ufw rules files.
Important: ufw only uses the *filter table by default. You may add any other tables such as *nat, *raw and *mangle as desired. For each ta-
ble a corresponding COMMIT statement is required.
After modifying any of these files, you must reload ufw for the rules to take effect. See the EXAMPLES section for common uses of these
rules files.
MODULES
Netfilter has many different connection tracking modules. These modules are aware of the underlying protocol and allow the administrator to
simplify his or her rule sets. You can adjust which netfilter modules to load by adjusting IPT_MODULES in /etc/default/ufw. Some popular
modules to load are:
nf_conntrack_ftp
nf_nat_ftp
nf_conntrack_irc
nf_nat_irc
nf_conntrack_netbios_ns
nf_conntrack_pptp
KERNEL PARAMETERS
ufw will read in /etc/ufw/sysctl.conf on boot when enabled. Please note that /etc/ufw/sysctl.conf overrides values in the system
systcl.conf (usually /etc/sysctl.conf). Administrators can change the file used by modifying /etc/default/ufw.
IPV6
IPv6 is enabled by default. When disabled, all incoming, outgoing and forwarded packets are dropped, with the exception of traffic on the
loopback interface. To adjust this behavior, set IPV6 to 'yes' in /etc/default/ufw. See the ufw manual page for details.
EXAMPLES
As mentioned, ufw loads its rules files into the kernel by using the iptables-restore and ip6tables-restore commands. Users wanting to add
rules to the ufw rules files manually must be familiar with these as well as the iptables and ip6tables commands. Below are some common
examples of using the ufw rules files. All examples assume IPv4 only and that DEFAULT_FORWARD_POLICY in /etc/default/ufw is set to DROP.
IP Masquerading
To allow IP masquerading for computers from the 10.0.0.0/8 network to share the single IP address on eth0:
Edit /etc/ufw/sysctl.conf to have:
net.ipv4.ip_forward=1
Add to the end of /etc/ufw/before.rules, after the *filter section:
*nat
:POSTROUTING ACCEPT [0:0]
-A POSTROUTING -s 10.0.0.0/8 -o eth0 -j MASQUERADE
COMMIT
If your firewall is using IPv6 tunnels or 6to4 and is also doing NAT, then you should not usually masquerade protocol '41' (ipv6) packets.
For example, instead of the above, /etc/ufw/before.rules can be adjusted to have:
*nat
:POSTROUTING ACCEPT [0:0]
-A POSTROUTING -s 10.0.0.0/8 --protocol ! 41 -o eth0 -j MASQUERADE
COMMIT
Port Redirections
To forward tcp port 80 on eth0 to go to the webserver at 10.0.0.2:
Edit /etc/ufw/sysctl.conf to have:
net.ipv4.ip_forward=1
Add to the *filter section of /etc/ufw/before.rules:
-A ufw-before-forward -m state --state RELATED,ESTABLISHED
-j ACCEPT
-A ufw-before-forward -m state --state NEW -i eth0
-d 10.0.0.2 -p tcp --dport 80 -j ACCEPT
Add to the end of /etc/ufw/before.rules, after the *filter section:
*nat
:PREROUTING ACCEPT [0:0]
-A PREROUTING -p tcp -i eth0 --dport 80 -j DNAT
--to-destination 10.0.0.2:80
COMMIT
Egress filtering
To block RFC1918 addresses going out of eth0:
Add in the *filter section of /etc/ufw/before.rules:
-A ufw-before-forward -o eth0 -d 10.0.0.0/8 -j REJECT
-A ufw-before-forward -o eth0 -d 172.16.0.0/12 -j REJECT
-A ufw-before-forward -o eth0 -d 192.168.0.0/16 -j REJECT
Full example
This example combines the other examples and demonstrates a simple routing firewall. Warning: this setup is only an example to demonstrate
the functionality of the ufw framework in a concise and simple manner and should not be used in production without understanding what each
part does and does not do. Your firewall will undoubtedly want to be less open.
This router/firewall has two interfaces: eth0 (Internet facing) and eth1 (internal LAN). Internal clients have addresses on the 10.0.0.0/8
network and should be able to connect to anywhere on the Internet. Connections to port 80 from the Internet should be forward to 10.0.0.2.
Access to ssh port 22 from the administrative workstation (10.0.0.100) to this machine should be allowed. Also make sure no internal traf-
fic goes to the Internet.
Edit /etc/ufw/sysctl.conf to have:
net.ipv4.ip_forward=1
Add to the *filter section of /etc/ufw/before.rules:
-A ufw-before-forward -m state --state RELATED,ESTABLISHED
-j ACCEPT
-A ufw-before-forward -i eth1 -s 10.0.0.0/8 -o eth0 -m state
--state NEW -j ACCEPT
-A ufw-before-forward -m state --state NEW -i eth0
-d 10.0.0.2 -p tcp --dport 80 -j ACCEPT
-A ufw-before-forward -o eth0 -d 10.0.0.0/8 -j REJECT
-A ufw-before-forward -o eth0 -d 172.16.0.0/12 -j REJECT
-A ufw-before-forward -o eth0 -d 192.168.0.0/16 -j REJECT
Add to the end of /etc/ufw/before.rules, after the *filter section:
*nat
:PREROUTING ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
-A PREROUTING -p tcp -i eth0 --dport 80 -j DNAT
--to-destination 10.0.0.2:80
-A POSTROUTING -s 10.0.0.0/8 -o eth0 -j MASQUERADE
COMMIT
For allowing ssh on eth1 from 10.0.0.100, use the ufw command:
# ufw allow in on eth1 from 10.0.0.100 to any port 22 proto tcp
SEE ALSO ufw(8), iptables(8), ip6tables(8), iptables-restore(8), ip6tables-restore(8), sysctl(8), sysctl.conf(5)AUTHOR
ufw is Copyright 2008-2009, Canonical Ltd.
ufw and this manual page was originally written by Jamie Strandboge <jamie@canonical.com>
August 2009 UFW FRAMEWORK(8)