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Firewall (view source)

Revision as of 11:50, 11 October 2018

5,990 bytes added ,  11:50, 11 October 2018
→‎Block incoming IP address
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==Firewall==
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{{usefulnote}}
 
The server manager is the GUI front end for the firewall. The firewall is modified automatically in response to changes you make in the configuration, such as enabling/disabling services, marking them public/private, forwarding ports, etc.
 
The server manager is the GUI front end for the firewall. The firewall is modified automatically in response to changes you make in the configuration, such as enabling/disabling services, marking them public/private, forwarding ports, etc.
    
If you wish to make changes beyond those provided for by the server manager, you can do so by setting DB records or providing custom templates. Only make these changes if you are sure you know what you are doing, '''incorrect settings will compromise security on your server.'''
 
If you wish to make changes beyond those provided for by the server manager, you can do so by setting DB records or providing custom templates. Only make these changes if you are sure you know what you are doing, '''incorrect settings will compromise security on your server.'''
   −
===FAQs===
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==FAQs==
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*I want to have two WAN addresses; one for the SMESERVER and another that needs to be treated like a "Local Network". I can't set any address from the WAN subnet as a "Local Network".
 
*I want to have two WAN addresses; one for the SMESERVER and another that needs to be treated like a "Local Network". I can't set any address from the WAN subnet as a "Local Network".
    
This is intended behaviour as SMESERVER is secure by design. If you need to do something like this, you should know what you are doing and understand what to poke under the covers.
 
This is intended behaviour as SMESERVER is secure by design. If you need to do something like this, you should know what you are doing and understand what to poke under the covers.
   −
 
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==DB Settings==
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*How do I allow public access to a service I've added to SME Server?
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===DB Settings===
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For this example the service you have installed is called 'manta' and 'nnn' is the TCP port number that needs to be opened. Watch your capitalization with the command below:
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*How do I allow public access to a service I've added to SME Server 7?
  −
The procedure has changed and is now much simpler in SME Server 7. For this example the service you have installed is called 'manta' and 'nnn' is the TCP port number that needs to be opened. Watch your capitalization with the command below:
   
    
 
    
 
   config set manta service access public status enabled TCPPort nnn
 
   config set manta service access public status enabled TCPPort nnn
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   signal-event remoteaccess-update
 
   signal-event remoteaccess-update
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*I want to block traffic from some ip-addresses to my server on some port.
 
*I want to block traffic from some ip-addresses to my server on some port.
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  signal-event post-upgrade
 
  signal-event post-upgrade
 
  signal-event reboot
 
  signal-event reboot
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===Additional information on customizing iptables===
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Create a custom-named service definition in the configuration database. you can see the [[DB_Variables_Configuration#Additional_information_on_customizing_iptables|DB configuration]]
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db configuration set <servicename> service
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Apply your desired firewall restrictions to any existing SME 'service' or to a custom-named service that you have created. Combine a custom-named service with port-forwarding to create customized firewall rules.
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db configuration setprop <servicename> TCPPort <portnumber>
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db configuration setprop <servicename> TCPPorts <portnumbers>
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db configuration setprop <servicename> UDPPort <portnumber>
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db configuration setprop <servicename> UDPPorts <portnumbers>
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db configuration setprop <servicename> status enabled|disabled
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db configuration setprop <servicename> access public|private
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db configuration setprop <servicename> AllowHosts a.b.c.d,x.y.z.0/24
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db configuration setprop <servicename> DenyHosts e.f.g.h,l.m.n.0/24
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 +
Effectuate the changes you have made
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signal-event remoteaccess-update
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 +
{| border="1" width="100%" cellspacing="0" cellpadding="5"
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|+Affected file: /etc/rc.d/init.d/masq
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!Variable
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!Target
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!Default
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!Expected values
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|-
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|TCPPort
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| --proto tcp --dport <Ports>
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|Pre-configured for default services; no default for custom services
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|empty or a numerical or coma separated numbers 
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|-
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|TCPPorts
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| --proto tcp --dports <Ports>
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|No default for custom services; Ranges of ports are defined with a : not a -
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|empty or a numerical or coma separated numbers 
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|-
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|UDPPort
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| --proto udp --dport <Ports>
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|Pre-configured for default services; no default for custom services
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|empty or a numerical or coma separated numbers 
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|-
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|UDPPorts
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| --proto udp --dports <Ports>
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|No default for custom services; Ranges of ports are defined with a : not a -
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|empty or a numerical or coma separated numbers 
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|-
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|status
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| enabled | disabled
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|AllowHosts is set to "" (an empty string) unless the status is 'enabled'
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|'enabled' or 'disabled'
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|-
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|access
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| public | private
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|AllowHosts is set to "" (an empty string) unless access is 'public'
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|'private' for localhost and local network only (Server and gateway mode), 'public' for everywhere, 'localhost' for localhost only
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|-
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|AllowHosts
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| --src ..... --jump ACCEPT
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|Pre-configured for default services; no default for custom services.  Default is '0.0.0.0/0' if service is ''enabled'' and ''public''.
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|IP and netmask  with this format 0.0.0.0/0, or coma separated list of these elements
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|-
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|DenyHosts
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| --src ..... --jump denylog
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|Pre-configured for default services; no default for custom services.  If 'DenyHosts' is empty or does not exist then there are no '... --jump denylog' entries created in /etc/init.d/masq.
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|IP and netmask  with this format 0.0.0.0/0, or coma separated list of these elements
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|}
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 +
==Custom templates==
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===Block incoming IP address===
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===Custom templates===
  −
====Block incoming IP address====
   
*I want to block All traffic from some ip-addresses to my server.
 
*I want to block All traffic from some ip-addresses to my server.
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 +
====Manual Method====
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Create a custom template and list the IP's
 
Create a custom template and list the IP's
 
  mkdir -p /etc/e-smith/templates-custom/etc/rc.d/init.d/masq/
 
  mkdir -p /etc/e-smith/templates-custom/etc/rc.d/init.d/masq/
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  pico -w /etc/e-smith/templates-custom/etc/rc.d/init.d/masq/40DenyRiffRaff
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  nano -w /etc/e-smith/templates-custom/etc/rc.d/init.d/masq/40DenyRiffRaff
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Now add the IP's you wish to block to the newly create file in the following format.
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  /sbin/iptables -A INPUT -s 69.212.12.76/32 -j DROP
 
  /sbin/iptables -A INPUT -s 69.212.12.76/32 -j DROP
 
  /sbin/iptables -A INPUT -s 88.28.215.11/32 -j DROP
 
  /sbin/iptables -A INPUT -s 88.28.215.11/32 -j DROP
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  /sbin/e-smith/expand-template /etc/rc.d/init.d/masq
 
  /sbin/e-smith/expand-template /etc/rc.d/init.d/masq
 
  /etc/init.d/masq restart
 
  /etc/init.d/masq restart
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 +
To check the new block use the following command and look for the IP address you just DROP'ed. It should be listed in the "source" column.
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  iptables -L INPUT -v -n
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====Automated method====
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 +
The above can be automated slightly.
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First lets create a key where we can add IPs that we want to block:
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config set ipblock configuration status enabled DenyHosts 208.100.26.0/24 logging disabled
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As above, create the following template:
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mkdir -p /etc/e-smith/templates-custom/etc/rc.d/init.d/masq/
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nano -w /etc/e-smith/templates-custom/etc/rc.d/init.d/masq/40DenyRiffRaff
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Paste this code:
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{
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    use esmith::ConfigDB;
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    my $db = esmith::ConfigDB->open_ro || die 'Could not open configuration database';
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    # Completely block any riff raff
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    if ( ( my $status = $db->get_prop( 'ipblock', 'status' ) ) eq 'enabled' ) {
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        my $DenyHosts = $db->get_prop( 'ipblock', 'DenyHosts' ) || '';
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        my $logging  = $db->get_prop( 'ipblock', 'logging' )  || 'disabled';
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        foreach my $host ( split( ',', $DenyHosts ) ) {
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            $OUT .= "\n";
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            $OUT .= "    # Simple IP block for riff raff\n\n";
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            if ( $logging eq 'enabled' ) {
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                $OUT .= "    /sbin/iptables -A INPUT -s $host -j denylog\n";
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            }
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            else {
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                $OUT .= "    /sbin/iptables -A INPUT -s $host -j DROP\n";
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            }
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            $OUT .= "\n";
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        }
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    }
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}
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You can add multiple addresses separated by commas:
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config setprop ipblock DenyHosts 208.100.26.0/24,1.2.3.4,5.6.0.0/16
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====Block outgoing ports====
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You can disable this blocking with:
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config setprop ipblock status disabled
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If you want to log the dropped packets rather than just drop them:
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config setprop ipblock logging enabled
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Then expand and restart your firewall:
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/sbin/e-smith/expand-template /etc/rc.d/init.d/masq
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/etc/init.d/masq restart
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===Block outgoing IPs or mac addresses===
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This section needs improvement.
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See this forum post for clues re doing this, based in part on the concept of blocking incming traffic from specific external IPs.
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 +
http://forums.contribs.org/index.php/topic,46036.0/all.html
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Formulation of suitable iptables rules will be required, use
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man iptables
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The template fragment needs to be placed in the right order, so that other rules do not negate the rule eg
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20blockIP
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Example:
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To block access based on the mac address of the NIC of the wokstation (not on IP)
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mkdir -p /etc/e-smith/templates-custom/etc/rc.d/init.d/masq/
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pico -w /etc/e-smith/templates-custom/etc/rc.d/init.d/masq/20Blockmac
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Add the following code to the fragment and save
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/sbin/iptables -A INPUT -m mac --mac-source XX:XX:XX:XX:XX:XX -j DROP
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(Replace XX.XX.XX.XX.XX.XX with actual mac address)
 +
 
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expand-template /etc/rc.d/init.d/masq
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/etc/init.d/masq restart
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Check that blocking works as expected
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 +
To see the iptables that are in effect on your server, issue the command
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iptables --list
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or
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iptables -L
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 +
===Block outgoing ports===
 
*I want to block outgoing traffic from my server.
 
*I want to block outgoing traffic from my server.
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  /etc/init.d/masq restart
 
  /etc/init.d/masq restart
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====Bypass Proxy====
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===Bypass Proxy===
 
*You have Transparent Proxy enabled (the default) but want to allow this to be selectively bypassed.
 
*You have Transparent Proxy enabled (the default) but want to allow this to be selectively bypassed.
   Line 102: Line 256:  
  expand-template /etc/rc.d/init.d/masq
 
  expand-template /etc/rc.d/init.d/masq
 
  /etc/init.d/masq restart
 
  /etc/init.d/masq restart
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If the setting changes do not appear to take effect, do the following
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signal-event reboot
 
To add a BypassProxyFrom IP & retain existing IPs without re-entering them, do the following
 
To add a BypassProxyFrom IP & retain existing IPs without re-entering them, do the following
 
  config setprop squid BypassProxyFrom a.b.c.d,$(config getprop squid BypassProxyFrom)
 
  config setprop squid BypassProxyFrom a.b.c.d,$(config getprop squid BypassProxyFrom)
 
  expand-template /etc/rc.d/init.d/masq
 
  expand-template /etc/rc.d/init.d/masq
 
  /etc/init.d/masq restart
 
  /etc/init.d/masq restart
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Followed if necessary by
 +
signal-event reboot
 
To remove a specific entry but leave other existing entries unchanged
 
To remove a specific entry but leave other existing entries unchanged
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  config setprop squid BypassProxyFrom $(config getprop squid BypassProxyFrom | sed -e 's/entry-to-be-removed//' -e 's/^,//' -e 's/,$//' -e 's/,,//')
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  config setprop squid BypassProxyFrom \
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$(config getprop squid BypassProxyFrom | \
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sed -e 's/entry-to-be-removed//' -e 's/^,//' -e 's/,$//' -e 's/,,//')
    
where entry-to-be-removed is the IP to be removed
 
where entry-to-be-removed is the IP to be removed
    
Note: The first sed is to remove the entry, the last second is to remove the comma at the beginning, the second for a comma at the end and the last to remove the double comma when an entry is removed at the middle of the list.
 
Note: The first sed is to remove the entry, the last second is to remove the comma at the beginning, the second for a comma at the end and the last to remove the double comma when an entry is removed at the middle of the list.
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Disable bypass:  
 
Disable bypass:  
Line 121: Line 278:  
  expand-template /etc/rc.d/init.d/masq
 
  expand-template /etc/rc.d/init.d/masq
 
  service masq restart
 
  service masq restart
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signal-event reboot
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<noinclude>[[Category:Howto]]</noinclude>
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==Open Ports in Private Server/Gateway Mode==
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===Open Ports in Private Server/Gateway Mode===
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*I want to hide all ports, so I put my SMESERVER in PRIVATE SERVER/GATEWAY mode. I can still see some ports are open.
 
*I want to hide all ports, so I put my SMESERVER in PRIVATE SERVER/GATEWAY mode. I can still see some ports are open.
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  signal-event post-upgrade
 
  signal-event post-upgrade
 
  signal-event reboot
 
  signal-event reboot
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 +
<noinclude>
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 +
 +
----
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[[Category:Howto]]
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[[Category:Administration]]
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[[Category:Security]]
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</noinclude>
Retrieved from "https://wiki.koozali.org/Special:MobileDiff/13228...35879"

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