Been running PiHole for a couple of months now, works great except for the issue in my thread title which came up when I transitioned from a Pi2 to a Pi3 (complete fresh install on Jessie Lite). The basic DNS functionality & ad-blocking works fine, but then I noticed:
PiHole doesn't respond to DNS queries originating from gateway router
PiHole cannot ping the gateway or further upstream (but DNS queries work fine). [Well actually the pings do work, Wireshark shows it working as expected, but it's just showing 100% packet loss on the SSH command line.]
Pihole -r wont download any packages
Pihole -d cant upload debug file
Admin console takes exactly 3 minutes between point of request on client PC and actual web page displaying (generally first time use after a period of inactivity, subsequent click/responses are rapid)
I had assumed that PiHole would just install and run fine on a Pi3 - but it doesn't! What might I be missing...?
Think we do not have sufficient info for an analysis. Let me take your points one by one:
1: How do you know this?
2: If pings are sent but report 100% packet loss it may be that ICMP traffic is blocked in a firewall.
3: This may be because you do not have internet connectivity
4: Same as #3
5: This may have to do with processes needing wake up after falling asleep after inactivity.
So my questions:
a: Can you show the output of traceroute to 8.8.8.8?
b: Is your Pi server set to fall asleep with Wake on Lan?
c: Do you have a firewall configured?
d: Did you use IPTables on the Pi server?
Ah, my apologies. It turns out that it was entirely my mistake - the router had got the wrong MAC address for the Pi3. This seriously messes up low level network functions! I overlooked the fact that there was a MAC-binding in the DHCP assignment table dating back to when one of the Pi's was used as a media centre - but now Pi Hole is definitely the killer app as far as I'm concerned!
Thanks for your support and good questions, they got me probing further with Wireshark and helped me spot the MAC discrepancy.