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 From:  William Arlofski <waa dash m0n0wall at revpol dot com>
 To:  m0n0wall at lists dot m0n0 dot ch
 Subject:  Re: [m0n0wall] ** SOLVED ** Internal machines accessing PPTP clients
 Date:  Thu, 13 Jan 2005 11:21:22 -0500
Ok after a long day and many different attempts, we made our way around
this issue (limitation?).

The solution was to insert a rule before the default block rule by
utilizing the <shellcmd> directive in the <system> block of the
config.xml file.

<shellcmd>echo @14 pass out quick from 192.168.1.0/24 to
192.168.100.16/28 keep state group 0 | ipf -f -</shellcmd>

Even though there is a rule in the gui on the LAN interface that says
allow all traffic, any protocol from 192.168.1.0/24 to anywhere on any
port, packets from 192.168.1.0/24 to PPTP clients were still being
blocked and logged by the default rule.

The rule that m0n0 generates from this LAN rule in the gui looks like:

@2 pass in quick from 192.168.1.0/24 to any keep state group 100

Which puts the rule in group 100, and the packets should be passed.

The rule added with the shellcmd above is put into the default group,
before the default block all rule, and allows the packets to pass OUT on
any interface.

This gets packets past being blocked on their way OUT of the ng[1-16]
PPTP interface(s) as they were in the log snip in the original post below.

Thanks to GeekGOd in #m0n0wall for all the time and effort yesterday. I
thank you and my client thanks you.

Perhaps you would like to follow-up on what I have stated above? Any
suggestions or future feature requests?  :)






William Arlofski wrote:
|
| Sorry for such a long post, but I can't find anything similar to my
| problem in the list archives, and I can not think of a quicker way to
| resolve this.
|
| I am having an issue allowing Internal workstations access to external
| PPTP clients.  The Internal workstations I am referring to are NOT on
| M0n0wall's "LAN Network" but are on a separate, private network
| connected to M0n0wall's "LAN Network" by a Linux Iptables Firewall.
|
| M0n0wall is blocking these Internal machines from connecting TO remote
| PPTP clients, but is allowing clients on its "LAN network" to connect to
| these very same PPTP clients.
|
| Below is an ASCII art drawing of the network in question, followed by
| additional info.  Any help would be appreciated.
|
|
| http://www.revpol.com/pptp.html
|
| - All networks are /24
|
| - There is an additional (not shown) 192.168.2.0/24 LAN routed
| separately, but not relevant to this problem.
|
| - M0n0wall LAN IP is 192.168.100.2
|
| - PPTP clients are 192.168.100.16-30/28
|
| - PPTP clients have been allowed - via very restrictive rules on the
| Linux Iptables firewall server - access to specific internal servers, on
| specific ports.  This works as expected.
|
| - Customer also wants VNC access (port 5900-5902) to connected PPTP
| clients from Internal workstation on 192.168.1.0/24 network.
|
| - Rules to allow 192.168.1.0/24 to access PPTP clients on ports
| 5900-5902 are in place on Linux IPtables firewall and on M0n0wall.
| Actually, for testing purposes there are rules to allow ALL traffic from
| 192.168.1.0/24 and 192.168.2.0/24 to m0n0.
|
| - VNC packets from internal workstation (192.168.1.9) are properly being
| passed by the IPtables firewall, and are hitting the M0n0wall box but
| are being blocked by M0n0wall's @0:16 default block rule. Here is a snip
| from remote syslog server:
|
|  Jan 10 21:31:55 192.168.100.2 ipmon[78]: 21:31:55.083569 ng1 @0:16 b
| 192.168.1.9,33161 -> 192.168.100.16,5900 PR tcp len 20 60 -S OUT
|
| Here are the group 0 rules from status.php on the M0n0wall:
| (BTW, I prefer my WAN interface to be number "0" so sis0 is WAN and sis1
| is LAN)
|
| @1 pass out quick on lo0 from any to any
| @2 pass out quick on sis1 proto udp from 192.168.100.2/32 port = 67 to
| any port = 68
| @3 pass out quick on sis1 from 192.168.100.0/24 to 192.168.1.0/24
| @4 pass out quick on sis1 from 192.168.1.0/24 to 192.168.100.0/24
| @5 pass out quick on sis1 from 192.168.100.0/24 to 192.168.2.0/24
| @6 pass out quick on sis1 from 192.168.2.0/24 to 192.168.100.0/24
| @7 pass out quick on sis0 proto udp from any port = 68 to any port = 67
| @8 pass out quick on sis0 proto udp from MonoWanIP/32 port = 500 to any
| @9 pass out quick on sis0 proto esp from MonoWanIP/32 to any
| @10 pass out quick on sis0 proto ah from MonoWanIP/32 to any
| @11 pass out quick on sis1 proto udp from 192.168.100.2/32 port = 500 to
| any
| @12 pass out quick on sis1 proto esp from 192.168.100.2/32 to any
| @13 pass out quick on sis1 proto ah from 192.168.100.2/32 to any
| @14 pass out quick on sis1 from any to any keep state
| @15 pass out quick on sis0 from any to any keep state
| @16 block out log quick from any to any
|
| - VNC from test client on 192.168.100/24 LAN to PPTP clients works as
| expected.
|
| If any additional information is rewquired, please ask. I'd like to
| either resolve this or tell my client that it is not possible.
|
|
| Thanks in advance.
|
|
| Bill Arlofski





--
Bill Arlofski
waa dash m0n0wall at revpol dot com