Extremely weird issue with Ping, randomly gives Host not found...help!

[scsi stud]

I have an issue, and I hope you all can help. I recently purchased a Netgear WNDR3700 router (v4) and flashed the router with DD-WRT firmware (the router is very new so the only firmware available is still in 'pre-release'. For the most part, everything has been working great.

However, I am having a very weird DNS/ping issue on my local network. Basically, the connectivity between the various connected devices is intermittent, when it comes to accessing by host name. For example:

1) Pinging PC 2 from PC 1 (using host name) returns valid correct result
2) Pinging PC 1 from PC 2 (using host name) sometimes returns 'host not found', and sometimes it just starts working
3) I have a server running Windows Hyper-V 2012 (Core) with 1 VM installed. From any machine on the network, I can ping the VM (Guest) just fine using hostname, but no machine on the network can ping the Hyper-V host by hostname. Including the guest.. the Guest OS cannot ping its Host, it says Host not found...

I can ping all machines by IP address just fine, it's the hostnames that are not working 100%.

Sometimes, however, if I try and ping the Hyper-V host over and over again, sometimes after the Nth time (usually 5-6th), the Ping returns back with the proper response. And then after about 15 minutes, it goes back to "host not found".

When I use NSLookup {hostname}, it correctly returns back the correct result. It's strictly ping that is not working.

I thought it may be due to the way DD-WRT is handling DNS... any ideas?

This is driving me insane.. any help would be greatly appreciated. Thanks in advance.

 

[xperan.rich]

I'd say there's something wrong with your DNS Somewhere, might be worth checking DHCP Scope to see if the correct DNS server is being used, also check your DNS Server, for any ropey looking entries

 

[scsi stud]

Thanks for the reply. I'm going to detail my exact setup to help better troubleshoot this:

Wireless Router:
Netgear WNDR3700 router (v4)
DHCP Enabled, DNSMasq Enabled
Has Static entry for Machine 4 (below)

Machine 1:
Win8 Pro Desktop
Connected to Domain
Attached to Router: Wired
Dynamic IP address
DNS: gets DNS from Machine 4

Machine 2:
Win8 Pro (Surface Pro)
Connected to Workgroup (not Domain as Machine 1 is)
Attached to Router: Wireless
Dynamic IP address
DNS: Dynamic (i.e., Router)

Machine 3:
Windows Server 2012 Hyper-V (Core)
Connected to Workgroup
Attached to Router: Wired
Dynamic IP address
DNS: Dynamic (i.e., Router)

Machine 4:
**Virtual Machine**: Windows Server Essentials 2012
This machine is a Domain Controller (Machine 1 is a member of this Domain)
This is a Guest VM of Machine 3 (i.e., Machine 3 is hosting this VM)
Static IP address
Attached to Router: Wired (via Host OS).. this VM has an "external" network adapter that I specified so it can communicate with other physical machines on the local network
DNS: Set to itself (127.0.0.1)

The #1 issue I am having is that Machine 3 (the Hyper-V HOST) can PING ALL the other machines successfully, but NONE of the other machines (Machine 1, 2, or 4) can PING Machine 3.

Sometimes, very rarely, all of a sudden, Machine 3 is successfully pingable by the other 3 machines (For example, Ping keeps giving host not found, but all of a sudden it starts working), but usually after 15-20 minutes, it stops working again.

Since Machine 1 is connected via Domain to Machine 4, and since Machine 4 is a Domain Controller, Machine 1's DNS is pointing to Machine 4. Machine 1 has no problems pinging all other machines besides Machine 3.

Regarding Machine 2 (Surface Pro), for the most part it works good, however, sometimes it has trouble pinging Machine 1. Though it's a minor quirk and I blame that mostly on the Wifi adapter in the Surface Pro to being junky.

I hope this helps.

 

[VirtualLarry]

You should set machine 3's DNS to machine 4's IP.

With machine 3's DNS set to the router, then when machine 3 boots, it registers its hostname with the router. Machine 1 and 4 are using Machine 4 for DNS, right? So machine 3 is not registering its hostname with machine 4's DNS. So when machine 1 or 4 lookup the hostname of machine 3, they can't find it.

 

[spidey07]

Windows is using netbios for name resolution. Turn off netbios over tcp/ip on every single device.

nslookup is a pure DNS lookup tool, so it looks like DNS is good.