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Top Forums UNIX for Dummies Questions & Answers iptables to block port 25 only to a certain range Post 302897064 by holyearth on Thursday 10th of April 2014 05:30:39 PM
Old 04-10-2014
iptables to block port 25 only to a certain range

I want to limit all *outbound* traffic on eth0 (or all *.*) on port 25 to a specific (allowed) range...

I.E.
192.168.1.5 (local ip) tries to connect to 1.2.3.4:25 (outside real world ip)

It can proceed because 1.2.3.0/24 is the allowed range

Now, 192.168.1.5 (local ip) tries to connect to 2.3.4.5:25 it is not allowed (drop?) because 2.3.4.5 is not part of the 1.2.3.0/24

Thanks for the help I could not find a way to do this:

This did not work:
iptables -A OUTPUT -o eth0 -p tcp -d 1.2.3.0/24 --dport 25 -m state --state NEW,ESTABLISHED -j ACCEPT


Thanks!
 

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SHOREWALL-ROUTESTOP(5)						  [FIXME: manual]					    SHOREWALL-ROUTESTOP(5)

NAME
routestopped - The Shorewall file that governs what traffic flows through the firewall while it is in the 'stopped' state. SYNOPSIS
/etc/shorewall/routestopped DESCRIPTION
This file is used to define the hosts that are accessible when the firewall is stopped or is being stopped. Warning Changes to this file do not take effect until after the next shorewall start or shorewall restart command. The columns in the file are as follows (where the column name is followed by a different name in parentheses, the different name is used in the alternate specification syntax). INTERFACE - interface Interface through which host(s) communicate with the firewall HOST(S) (hosts) - [-|address[,address]...] Optional. Comma-separated list of IP/subnet addresses. If your kernel and iptables include iprange match support, IP address ranges are also allowed. If left empty or supplied as "-", 0.0.0.0/0 is assumed. OPTIONS - [-|option[,option]...] Optional. A comma-separated list of options. The order of the options is not important but the list can contain no embedded whitespace. The currently-supported options are: routeback Set up a rule to ACCEPT traffic from these hosts back to themselves. Beginning with Shorewall 4.4.9, this option is automatically set if routeback is specified in shorewall-interfaces[1] (5) or if the rules compiler detects that the interface is a bridge. source Allow traffic from these hosts to ANY destination. Without this option or the dest option, only traffic from this host to other listed hosts (and the firewall) is allowed. If source is specified then routeback is redundant. dest Allow traffic to these hosts from ANY source. Without this option or the source option, only traffic from this host to other listed hosts (and the firewall) is allowed. If dest is specified then routeback is redundant. notrack The traffic will be exempted from conntection tracking. PROTO (Optional) - protocol-name-or-number Protocol. DEST PORT(S) (dport) - service-name/port-number-list Optional. A comma-separated list of port numbers and/or service names from /etc/services. May also include port ranges of the form low-port:high-port if your kernel and iptables include port range support. SOURCE PORT(S) (sport) - service-name/port-number-list Optional. A comma-separated list of port numbers and/or service names from /etc/services. May also include port ranges of the form low-port:high-port if your kernel and iptables include port range support. Note The source and dest options work best when used in conjunction with ADMINISABSENTMINDED=Yes in shorewall.conf[2](5). EXAMPLE
Example 1: #INTERFACE HOST(S) OPTIONS PROTO DEST SOURCE # PORT(S) PORT(S) eth2 192.168.1.0/24 eth0 192.0.2.44 br0 - routeback eth3 - source eth4 - notrack 41 FILES
/etc/shorewall/routestopped SEE ALSO
http://shorewall.net/starting_and_stopping_shorewall.htm http://shorewall.net/configuration_file_basics.htm#Pairs shorewall(8), shorewall-accounting(5), shorewall-actions(5), shorewall-blacklist(5), shorewall-hosts(5), shorewall_interfaces(5), shorewall-ipsets(5), shorewall-maclist(5), shorewall-masq(5), shorewall-nat(5), shorewall-netmap(5), shorewall-params(5), shorewall-policy(5), shorewall-providers(5), shorewall-proxyarp(5), shorewall-rtrules(5), shorewall-rules(5), shorewall.conf(5), shorewall-secmarks(5), shorewall-tcclasses(5), shorewall-tcdevices(5), shorewall-tcrules(5), shorewall-tos(5), shorewall-tunnels(5), shorewall-zones(5) NOTES
1. shorewall-interfaces http://www.shorewall.net/manpages/shorewall-interfaces.html 2. shorewall.conf http://www.shorewall.net/manpages/shorewall.conf.html [FIXME: source] 06/28/2012 SHOREWALL-ROUTESTOP(5)
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