bindinterfacesonly.xml [plain text]
<samba:parameter name="bind interfaces only"
context="G"
advanced="1" wizard="1" developer="1"
xmlns:samba="http://samba.org/common">
<listitem>
<para>This global parameter allows the Samba admin
to limit what interfaces on a machine will serve SMB requests. It
affects file service <citerefentry><refentrytitle>smbd</refentrytitle>
<manvolnum>8</manvolnum></citerefentry> and name service <citerefentry><refentrytitle>nmbd</refentrytitle>
<manvolnum>8</manvolnum></citerefentry> in a slightly different ways.</para>
<para>For name service it causes <command moreinfo="none">nmbd</command> to bind
to ports 137 and 138 on the interfaces listed in
the <link linkend="INTERFACES">interfaces</link> parameter. <command moreinfo="none">nmbd</command> also
binds to the "all addresses" interface (0.0.0.0)
on ports 137 and 138 for the purposes of reading broadcast messages.
If this option is not set then <command moreinfo="none">nmbd</command> will service
name requests on all of these sockets. If <parameter moreinfo="none">bind interfaces
only</parameter> is set then <command moreinfo="none">nmbd</command> will check the
source address of any packets coming in on the broadcast sockets
and discard any that don't match the broadcast addresses of the
interfaces in the <parameter moreinfo="none">interfaces</parameter> parameter list.
As unicast packets are received on the other sockets it allows
<command moreinfo="none">nmbd</command> to refuse to serve names to machines that
send packets that arrive through any interfaces not listed in the
<parameter moreinfo="none">interfaces</parameter> list. IP Source address spoofing
does defeat this simple check, however, so it must not be used
seriously as a security feature for <command moreinfo="none">nmbd</command>.</para>
<para>For file service it causes <citerefentry><refentrytitle>smbd</refentrytitle>
<manvolnum>8</manvolnum></citerefentry> to bind only to the interface list
given in the <link linkend="INTERFACES">interfaces</link> parameter. This
restricts the networks that <command moreinfo="none">smbd</command> will serve
to packets coming in those interfaces. Note that you should not use this parameter
for machines that are serving PPP or other intermittent or non-broadcast network
interfaces as it will not cope with non-permanent interfaces.</para>
<para>If <parameter moreinfo="none">bind interfaces only</parameter> is set then
unless the network address <emphasis>127.0.0.1</emphasis> is added
to the <parameter moreinfo="none">interfaces</parameter> parameter
list <citerefentry><refentrytitle>smbpasswd</refentrytitle>
<manvolnum>8</manvolnum></citerefentry> and <citerefentry><refentrytitle>swat</refentrytitle>
<manvolnum>8</manvolnum></citerefentry> may not work as expected due
to the reasons covered below.</para>
<para>To change a users SMB password, the <command moreinfo="none">smbpasswd</command>
by default connects to the <emphasis>localhost - 127.0.0.1</emphasis>
address as an SMB client to issue the password change request. If
<parameter moreinfo="none">bind interfaces only</parameter> is set then unless the
network address <emphasis>127.0.0.1</emphasis> is added to the
<parameter moreinfo="none">interfaces</parameter> parameter list then <command moreinfo="none">
smbpasswd</command> will fail to connect in it's default mode.
<command moreinfo="none">smbpasswd</command> can be forced to use the primary IP interface
of the local host by using its <citerefentry><refentrytitle>smbpasswd</refentrytitle>
<manvolnum>8</manvolnum></citerefentry> <parameter moreinfo="none">-r <replaceable>remote machine</replaceable></parameter>
parameter, with <replaceable>remote machine</replaceable> set
to the IP name of the primary interface of the local host.</para>
<para>The <command moreinfo="none">swat</command> status page tries to connect with
<command moreinfo="none">smbd</command> and <command moreinfo="none">nmbd</command> at the address
<emphasis>127.0.0.1</emphasis> to determine if they are running.
Not adding <emphasis>127.0.0.1</emphasis> will cause <command moreinfo="none">
smbd</command> and <command moreinfo="none">nmbd</command> to always show
"not running" even if they really are. This can prevent <command moreinfo="none">
swat</command> from starting/stopping/restarting <command moreinfo="none">smbd</command>
and <command moreinfo="none">nmbd</command>.</para>
<para>Default: <command moreinfo="none">bind interfaces only = no</command></para>
</listitem>
</samba:parameter>