Unable to touch the gateway

I use DHCP to get IP from my ISP at home.
I can get a public IP on Mac and ping the gateway is ok.
But I have a problem to ping the gateway on Guest OS:Windows XP.
I still use DHCP to get a IP and I got one,but the gateway is untouchable.
I thought the problem is the second IP I got is in the different net with first one.
For example:Mac got 221.169.xx.10/24 and the gatway is 221.169.xx.254.
Windows got 221.170.xx.10/24 with gateway 221.170.xx.254.
In the office I can get both IP in the same net which means gateway is the same.
So both Mac and Windows can connect to Internet.
My ISP can't provide me IPs in the same net.
Is there any solution can solve my problem?
I need public IP for some reasons,so using NAT does not fit for me.

 

danniellin,

I guess your VM is bridged to wired Ethernet Adapter, right? Actually, bridging doesn't care about IP addresses in this case.
I assume your ISP allows you to use more than 1 IP address. Otherwise I'd check with them first. I also assume you're pinging 221.170.xx.254 from windows. Can you disable OSX firewall temporarily to see if has any effect?

 

My VM is bridged to wireless Ethernet Adapter(Air Port).
Yes,I can get more than one IP address.
After I checked the firewall setting,I found it was disabled.
I try to restart OS X,and I got two new IP addresses.
Mac got 59.104.96.xx/22,Windows got 59.104.97.xx/22.
This two IP addresses was in the same net and have same gateway.
New situstion is Windows ping Mac....ok.
Mac ping Windows....Request timed out.
Mac to gateway....ok.
Windows to gateway....Request timed out.
I bring the laptop to the office and everything is fine.
Both Mac and Windows got 220.100.100.xx/24.
And the most important thing is Windows can surf and receive mail.
I didn't change any setting,why it works at office but failed at home.

 

Please check that Windows firewall is disabled too. Mac should be able to comminicate the VM even if you can't ping your router.

Do you plug your provider cable directly into your Mac or you have a hub/switch in the middle?

 

serv,
After I disabled the firewall on Windows,Mac ping Windows is ok now.
But Windows still can't ping anything except Mac and itself.
I set an Access Point be a wireless hub.
I have on desktop and two laptops.
All of them can connect to internet at the same time with different IP address and different gateway.

 

I didn't realize you're bridged to AirPort. Are you sure you're not using PPPoE to talk to your provider? Can you try plugging ethernet wire directly into Mac and see if anything changes?

 

I plugged the provider cable into the Lan port of my Access Point.
And my laptop and desktop connect to Access Point by wireless.
That's why I said it's a "Wireless Hub".
My ISP provide me two ways to get IP address,DHCP or PPPoE.
Both ways can get IP address on Macbook and my real Windows desktop.
If I choose PPPoE to get IP address for Windows under Parallels,I won't get any.
I will try your suggestion latter,thanks for your help.

 

serv,
Your solution solve my problem.
I thought the problem is my Access Point.
Thanks for your help,have a nice day.