Windows file sharing across subnets

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Level 1

5 points

Windows file sharing across subnets

I have a SonicWall TZ170 wireless router that will not allow the LAN and WLAN to have the same subnet IP address. I have a WinXP Pro desktop on the LAN at 192.168.70.100 and a PowerBook on the WLAN at 192.168.71.100. The router firewall is set up to allow all traffic (any IP address) between the two subnets. However, no matter what i do, I cannot get the PowerBook to connect to the PC. (I've also tried SMB://192.168.70.100/share, where "share" is the name of the shared folder on the PC.) I know the file sharing settings are correct, since I can mount the PC share when the PowerBook is connected to the LAN.

I've since read that SMB does not work over different subnets. Is this correct? If so, is there any other way to share files on the PC with the PowerBook?

PowerBook G4 15 Mac OS X (10.4.8)

Posted on Mar 4, 2007 11:50 AM

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Answer 1

Camelot

Level 9

58,563 points

Mar 4, 2007 12:04 PM in response to Cantelia

Is the wireless router running NAT? i.e. translating IP addresses from the wireless clients to an IP address on the wired side?

If so, that's likely to be the problem. SMB doesn't work well through NAT.

If the router was acting as a simple bridge you wouldn't have this problem.

Are you sure that the SonicWall requires different subnets I've never encountered that before - it's usually optional. If it is the case your only options are to either use a different protocol (which may be a problem since you're running Windows XP), or get a different router.

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Answer 2

Cantelia Author

Level 1

5 points

Mar 4, 2007 12:19 PM in response to Camelot

NAT is only used on the WAN. The LAN and WLAN are bridged using rules set up in the router firewall settings.

On the TZ170 wireless router, the LAN and WLAN MUST have different subnets. This is by design. SonicWall's reasoning is that they force you to put the WLAN on a different subnet to protect your VPN from wireless intrusion. (i.e. protect you from your own carelessness.) By default the LAN and WLAN are not bridged. You have to set up rules to allow traffic between the two.

PowerBook G4 15 Mac OS X (10.4.8)

PowerBook G4 15

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Answer 3

Camelot

Level 9

58,563 points

Mar 4, 2007 5:08 PM in response to Cantelia

> On the TZ170 wireless router, the LAN and WLAN MUST have different subnets

Wow. What a weird setup. I've never encountered that before.

Thanks for the heads-up. I know now to avoid SonicWall products 🙂

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Answer 4

Mar 5, 2007 11:31 AM in response to Cantelia

What subnet mask are you using?
There will be a mask that will permit traffic across.
I can't think if it just now.
Are there any subnet mask calculators on the internet?
Found one:
http://www.subnet-calculator.com/
I think you want your subnet mask to be 255.255.255.128
that allows two subnets.
Something like that?

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Answer 5

Mar 5, 2007 11:34 AM in response to Rick Van Vliet

Also. Do the mac and the XP share a workgroup name?
XP often defaults to MShome.
Mac's workgroup can be found in Directory Access>SMB/CIFS>Configure.
these must match

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Answer 6

Cantelia Author

Level 1

5 points

Mar 5, 2007 3:50 PM in response to Rick Van Vliet

I don't think changing the subnet mask will work. Please let me know if you have a link to something that says this will allow SMB traffic to traverse different subnets.

Regarding the workgroup name, both the PowerBook and the PC are using the name "HOME", so that's not the problem.

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Answer 7

BDAqua

Level 10

250,259 points

Mar 5, 2007 4:56 PM in response to Cantelia

Well, both Camelot & Rick know far more than I do on this, but it seems to me that if that Router is actually passing stuff then no Subnet Change would be needed, but if it needed to have the subnet cahanged, you'd need 255.255.254.0 for 192.168.70.100 to reach 192.168.71.100

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Answer 8

Camelot

Level 9

58,563 points

Mar 5, 2007 5:08 PM in response to Rick Van Vliet

Changing the subnet mask won't work.

Sure, you can come up with a subnet mask that encompasses the IP addresses on both the LAN and the WLAN, but that's not the point.

The point is that the router demands one subnet on the LAN and a different subnet on the WLAN. Changing the subnet mask only increases the size of the subnet on the LAN and if that expanded subnet encompasses the WLAN IPs then you're no longer running different subnets on the LAN and WLAN.

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Answer 9

Mar 5, 2007 5:47 PM in response to Camelot

Mmm, i guess you're right, there...camelot.
drat...
this is a good reason to avoid those SonicWalls 🙂

Message was edited by: Rick Van Vliet

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Answer 10

P Gierke

Level 1

70 points

Mar 5, 2007 8:05 PM in response to Cantelia

Check your Windows Firewall settings on the XP Pro PC. I've read that the default Windows Firewall settings will only allow connections to CIFS shares from clients that are on the same subnet. I suspect this is why you cannot connect to the PC from your Mac.

SMB will work across subnets. I access an SMB share via a PPTP tunnel managed by my home router. The share is on a different subnet than my local network, but I have no problem connecting.

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Answer 11

Mar 6, 2007 3:09 AM in response to P Gierke

Good thought re: Windows firewall.

My thought is...after looking at the exorbutant pricing on this SonicWall...is that cantelia should probably call their tech service and get the exact settings that this piece of junk needs. This seems a little silly that SonicWall doesn't include the basic settings required to do this simple networking basic (Samba sharing on wireless).
Two subnets required?? Hmm.

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Answer 12

Cantelia Author

Level 1

5 points

Mar 8, 2007 6:28 AM in response to Rick Van Vliet

Here's the reply from SonicWall:

"There is no direct solution to this design consideration in our firmware. We do not, indeed, allow the LAN and WLAN to share the same subnet. Firewall access rules may be used to allow traffic, or WiFiSec may be used by way of GVC or by trusting WPA traffic. Specifics at this point are probably best dealt with in the form of a call to our technical support team."

Any ideas?

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Answer 13

Mar 8, 2007 7:02 AM in response to Cantelia

Ideas?

I'm downloading the manuals, to see if I can glean any clues from there as far as configuring the firewall rules in the device.
I suggest that you do the same.
http://www.sonicwall.com/us/support/3134.html
There are several product guides and how-to PDF's...
The other idea that might work would be to follow their suggestion: "Specifics at this point are probably best dealt with in the form of a call to our technical support team."

this is looking less like a mac issue and more like a SonicWall issue.

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Answer 14

Cantelia Author

Level 1

5 points

Mar 8, 2007 9:18 AM in response to Rick Van Vliet

This problem is obviously caused by the subnet issue with the SonicWall, however I never said the solution would be with the SonicWall configuration.

Getting back to the core issue, is there a way for the Mac to access a shared folder on a Windows PC that is on a different subnet. Is this even possible? If not, why?

FYI, SonicWall tech support, like many others in this day and age, is completely useless. India-based call centers will be the demise of this and many other companies. Based on the lack of support we have experienced, this will be the last SonicWall product our company will purchase.

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