Modifying DNS servers using original MFDeploy results in incorrect behaviour when DHCP is enabled about netduino.ip HOT 4 CLOSED

After further investigation, I tried using the new MFDeploy tool with IPv6 settings. Even using that tool, and even if the DNS servers are first programmed with valid static values, enabling DHCP results in a NullReferenceException when reading the DNS servers, and an inability to resolve host names.

from netduino.ip.

Thank you for all of your tests, NameOfTheDragon.

Netduino.IP was relying on the "DHCP-specified DNS servers" flag, which is not necessarily set correctly from MFDeploy. For backwards compatibility, we will now treat an empty set of DNS server entries (all-zero) as an indication that DNS servers should be specified by DHCP (when DHCP-allocated IP config is enabled).

This is fixed for the Netduino.IP v1.0.1 release.

from netduino.ip.

My testing suggests that this isn't fixed (sorry). When I configure my Netduino Plus 2 for DHCP, I get a NullReferenceException when I try to read the nic.DnsServers property. Note: it is not returning null, any attempt to just read the property throws the NullReferenceException. Whatever way you look at it, it has got to be a bug for a property getter to throw a NullReferenceException no matter what state the network is in.

In my test code, which is based on your 'network time' sample, I have ensured that the link layer is active and that the NIC has a valid IP address (which also comes from DHCP, so DHCP itself must be working).

I have configured my Netduino with your 'special' version of MFDeploy that has the IPv6 settings pane. I have configured to obtain both the IP address and the DNS servers automatically. Attached is a screen shot of my settings.

from netduino.ip.

As a workaround, the DNS servers can be set to 0.0.0.0 in MFDeploy and then the network stack does work as expected - however the DnsAddresses property then returns an empty array, rather than the actual DNS servers being used. When I run my test code, I see the following output that shows DNS is actually working and has picked up the servers from DHCP:

[Network     ] Link layer available
[Network     ] Waiting for network layer
[Network     ] Network address changed:
[Network     ] 5C:86:4A:00:87:2C 192.168.16.7 (DHCP)
[Network     ] Found 1 network interfaces - details as follows...
[Network     ] Network interface: 0
[Network     ]   Interface type: 6
[Network     ]   IPv4 address: 192.168.16.7
[Network     ]   Default gateway: 192.168.16.1
[Network     ]   Subnet mask: 255.255.255.0
[Network     ]   No DNS servers - empty list returned
[Network Time] Attempting to set the time from pool.ntp.org
[Network Time] Resolved IP Address: 85.119.80.232
[Network Time] Network time received
[Network Time] UTC Time: 10/18/2015 17:44:26
[Unspecified ] Set system time to: 10/18/2015 17:44:26 UTC
[Unspecified ] Clock set to 10/18/2015 17:44:26

However, this is not what I would call "correct behaviour" since configuring the Netduino to use "automatic settings" simply doesn't work.

from netduino.ip.