Able to Ping host names without DNS installed, how is it working?

petekroll · 02-23-2009, 01:26 PM

Probably a simple question for most...
I have a small SOHO setup.
Cable Modem --> D-Link Router --> 2 PCs networked together using TCP/IP
I am just curious how it is letting me ping from one PC to the other by using the HOST name of the PC. I know pinging the IP should work but how can it ping the HOST name? How is this possible since I don't have a DNS server running and I haven't modified the HOSTS file to tell the PCs that this HOST name is tied to this IP address.
Does it have something to do with NetBIOS?
Thanks...just wanted to know how it works under the hood.
Sman

Tekmazter · 02-23-2009, 06:37 PM

More than likely your D-Link router is your DNS server.

Open a command prompt in Windows (START + RUN + cmd --> click OK)

type ipconfig /all

What is configured as your DNS server.

petekroll · 02-24-2009, 07:10 AM

Thanks.
It has to do with the NetBIOS which is able to resolve the PC name to IP address.

Tekmazter · 02-24-2009, 09:35 AM

So you're telling me you're not using DNS? Just exactly how do you browse the internet then?

Netbios will map names to ip addresses using a broadcast but if you're going to different subnets this will not work.

Go ahead and run a test for me ...

run ipconfig /displaydns

I'll bet you have dns resolution to your local LAN.

now run net view

I would recommend you always use DNS over netbios broadcasts especially when leveraging wireless.

02-23-2009, 01:26 PM	#1 (permalink)
petekroll Registered User Join Date: Nov 2002 Posts: 8 OS: XP	Able to Ping host names without DNS installed, how is it working? Probably a simple question for most... I have a small SOHO setup. Cable Modem --> D-Link Router --> 2 PCs networked together using TCP/IP I am just curious how it is letting me ping from one PC to the other by using the HOST name of the PC. I know pinging the IP should work but how can it ping the HOST name? How is this possible since I don't have a DNS server running and I haven't modified the HOSTS file to tell the PCs that this HOST name is tied to this IP address. Does it have something to do with NetBIOS? Thanks...just wanted to know how it works under the hood. Sman

02-23-2009, 06:37 PM	#2 (permalink)
Tekmazter Registered User Join Date: May 2008 Posts: 177 OS: XP / 2K3 / RHE / HP-UX	Re: Able to Ping host names without DNS installed, how is it working? More than likely your D-Link router is your DNS server. Open a command prompt in Windows (START + RUN + cmd --> click OK) type ipconfig /all What is configured as your DNS server.

02-24-2009, 07:10 AM	#3 (permalink)
petekroll Registered User Join Date: Nov 2002 Posts: 8 OS: XP	Re: Able to Ping host names without DNS installed, how is it working? Thanks. It has to do with the NetBIOS which is able to resolve the PC name to IP address.

02-24-2009, 09:35 AM	#4 (permalink)
Tekmazter Registered User Join Date: May 2008 Posts: 177 OS: XP / 2K3 / RHE / HP-UX	Re: Able to Ping host names without DNS installed, how is it working? So you're telling me you're not using DNS? Just exactly how do you browse the internet then? Netbios will map names to ip addresses using a broadcast but if you're going to different subnets this will not work. Go ahead and run a test for me ... run ipconfig /displaydns I'll bet you have dns resolution to your local LAN. now run net view I would recommend you always use DNS over netbios broadcasts especially when leveraging wireless.