[CentOS] Samba and iptables - woes

Craig White craigwhite at azapple.com
Tue Mar 31 05:33:33 UTC 2009


On Tue, 2009-03-31 at 00:19 -0400, Rob Kampen wrote:
> Hi folk,
> I am trying to get iptables working on a samba server but find it is 
> blocking something that prevents the windoze clients from being able to 
> access the share.
> here are the bits from iptables:
> > # nmb provided netbios-ns
> > -A RH-Firewall-1-INPUT -p udp -m udp -s 192.168.230.100/24 -i eth1 
> > --dport 137 -j ACCEPT
> > # nmb provided netbios-dgm
> > -A RH-Firewall-1-INPUT -p udp -m udp -s 192.168.230.100/24 -i eth1 
> > --dport 138 -j ACCEPT
> > # Samba
> > -A RH-Firewall-1-INPUT -p tcp -m tcp -m state -s 192.168.230.100/24 -i 
> > eth1 --dport 135 --state NEW -j ACCEPT
> > # smb provided netbios-ssn
> > -A RH-Firewall-1-INPUT -p tcp -m tcp -m state -s 192.168.230.100/24 -i 
> > eth1 --dport 139 --state NEW -j ACCEPT
> > # smb provided microsoft-ds
> > -A RH-Firewall-1-INPUT -p tcp -m tcp -m state -s 192.168.230.100/24 -i 
> > eth1 --dport 445 --state NEW -j ACCEPT
> so as far as I can tell this should provide access to the required services.
> BTW the server has two NICs; 100Mb is eth0 at 192.168.230.230 and 
> connects to the router with internet/NAT firewall; 1Gb is eth1 at 
> 192.168.230.232 and this connects to a G ethernet switch that has the 
> windoze clients.
> The smb.conf is as follows:
>  [global]
>         workgroup = NDG
>         netbios name = SAMBA
>         netbios aliases = Samba
>         server string = Samba Server Version %v
>         interfaces = lo, eth1, 192.168.230.232
>         bind interfaces only = Yes
>         security = DOMAIN
>         obey pam restrictions = Yes
>         passdb backend = tdbsam
>         pam password change = Yes
>         log file = /var/log/samba/%m.log
>         max log size = 50
>         load printers = No
>         add user script = /usr/sbin/useradd "%u" -n -g users
>         delete user script = /usr/sbin/userdel "%u"
>         add group script = /usr/sbin/groupadd "%g"
>         delete group script = /usr/sbin/groupdel "%g"
>         delete user from group script = /usr/sbin/userdel "%u" "%g"
>         add machine script = /usr/sbin/useradd -n -c "Workstation (%u)" 
> -M -d /nohome -s /bin/false "%u"
>         logon path =
>         domain logons = Yes
>         os level = 32
>         preferred master = Yes
>         domain master = Yes
>         dns proxy = No
>         wins support = Yes
>         ldap ssl = no
>         create mask = 0664
>         directory mask = 0775
>         hosts allow = 127., 192.168.230., 192.168.231.
>         case sensitive = Yes
>         browseable = No
>         available = No
>         wide links = No
>         dont descend = /
> 
> [homes]
>         comment = Home Directories
>         valid users = %S
>         read only = No
>         browseable = Yes
>         available = Yes
> 
> [NDG]
>         comment = NDG files
>         path = /NDG
>         write list = @NDGstaff, @birdseye
>         read only = No
>         browseable = Yes
>         available = Yes
> 
> I found that making the rule for port 139 ignore the eth port (i.e. 
> remove the -i eth1) allowed things to work better, but do not want this 
> to be the case as I do not want the eth0 interface to be used for this 
> traffic.
> looking at netstat -l -n shows only lo and eth1 listening on port 139, 
> so how is this failing to work??
> Any ideas?
> Thanks
----
I don't believe that you want to use comma separators in things like
'bind interfaces' or 'interfaces' - it doesn't seem that samba is
consistent here.

I have never used two separate hardware network interfaces on the same
subnet and suspect that it may actually be trying to communicate back
from the wrong one which is confusing things. Also, it doesn't make
sense to list both eth1 and the actual ip address in bind interfaces but
I would tend to doubt that would be a problem.

Try taking eth0 down (as root - ifdown eth0) and see if that fixes the
problem. 

Also, I'm not sure why some of the firewall rules include --state NEW
and some of the don't - that doesn't fully make sense to me.

Craig



More information about the CentOS mailing list