Virtual Machine fails to receive public IP address from ISP's DHCP Server

Network LayoutHi,

 I have VMWare box that came with two NICs. I use one NIC for internal servers and workstations and they are on 192.168.1.x network.
 The 2nd NIC is directly connected to the back of ISP internet modem for the virtual machiens that need direct connection to the internet by getting public dynamic IP addresses from ISP DHCP server and it has been working fine.
 Recently these virtual machines (under "Public IP -vSwitch1") fails to receive public IP from ISP's DHCP server. If I assign a static public IP (we have a set of 5 public IPs given by ISP) to these VMs, they work fine. However if I configure TCP/IP properties in these VMs to receive IP dynamically, it receives 192.168.1.x number as if it is under vSwitch0.
 Today I spoke to tech support at ISP and they confirmed that they still give out dynamic IP addresses to any device attached to their internet modem as long as it is set to receive dynamic IP.
So far, I have restarted these VMs, switched NIC between vSwitch0 and vSwitch1 on VMs, shutdown & start, even created a new virtual machine and assigned NIC to vSwitch1/Public IP group, but to no avail.
I have not restarted VMWare box yet.

 Any suggestions?

Thanks.
sgleeAsked:
Who is Participating?
 
Andrew Hancock (VMware vExpert / EE MVE^2)Connect With a Mentor VMware and Virtualization ConsultantCommented:
cross over cable from ISP modem to laptop and remove the switch!
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Today I spoke to tech support at ISP and they confirmed that they still give out dynamic IP addresses to any device attached to their internet modem as long as it is set to receive dynamic IP.
So far, I have restarted these VMs, switched NIC between vSwitch0 and vSwitch1 on VMs, shutdown & start, even created a new virtual machine and assigned NIC to vSwitch1/Public IP group, but to no avail.
I have not restarted VMWare box yet.

Please confirm, with a laptop if you connect a cable to the port on the Public ISP modem, an OS same OS as the VM gets an IP Address.

If you have confirmed by allocating a static IP Address to the VM, all networking is working, something, is either odd with VM or ISP.

We've seen this a number of times, and the fault often is with the ISP which has made changes, you will need to check as above....rule out the VMware environment.
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sgleeAuthor Commented:
Revised Network Layout.png@Andrew,
 
In my network diagram, I forgot to add a 8-port switch right behind ISP modem. Both CISCO router, my VMWare box and other WiFi devices are connected to this switch.
Per your request, I connected my laptop to this 8 port switch and it also received IP address: 192.168.1.x.
But even though my laptop has 192.168.1.x ip address, I can't ping any network servers & computers (on 192.168.1. network) behind CISCO router. I think I have a network device also connected to this 8 port switch that is doing DHCP server.
I need to investigate this ... I will report back.
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sgleeAuthor Commented:
I can't remove the switch as there are other devices connected to it. The CAT5e cable that is there between my 8-port switch and ISP modem has been there for years. So I don't think the problem is there.
I think I need to look into all the devices that are connected to this 8-port switch to see if any of them is performing DHCP server function.
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Andrew Hancock (VMware vExpert / EE MVE^2)Connect With a Mentor VMware and Virtualization ConsultantCommented:
something has changed somewhere....

so you are getting an IP Address bu not from the ISP, another DHCP server ?

Umm...
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sgleeAuthor Commented:
@Andrew,
 
 I found the culprit.
It was my test server (that was connected to the 8-port switch) was running DHCP server and I saw my laptop name listed in DHCP lease list. After I shut down my test server, I disabled and enabled NIC on my laptop and it received dynamic public IP address from ISP's DHCP server. So did other VMs under vSwitch1.

Thanks for your suggestion that I hook up my laptop to the ISP modem.
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Server Admin error!
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sgleeAuthor Commented:
My bad!
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