Author Topic: FPP2.1 default route issue  (Read 223 times)

Offline PeteyHall

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FPP2.1 default route issue
« on: October 05, 2018, 04:40:18 AM »
I've seen this issue with my two pi 3b's that I've upgraded to 2.1.  After a reboot, the pi keeps defaulting to the Ethernet port for it's DNS lookups which causes the pi not to be able to talk to Github because it can't do a DNS lookup.  If I do a ping to the DNS server 8.8.8.8 from the UI, I get a successful connection, so it's only the DNS lookup causing an issue.  The only way to resolve it is to go into the UI and tell it to restart the network.  Once the network restarts, DNS functions as expected.

I can confirm that the default gateway is only enabled on the wifi port, the eth0 port's gateway is blank and DNS is setup appropriately to manual and 8.8.8.8.

Anyone else seeing this?

Online JonB256

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Re: FPP2.1 default route issue
« Reply #1 on: October 05, 2018, 06:04:55 AM »
What do you have setup for eth0 and is there a CAT5 attached?

If I have no CAT5 attached, I don't have your problem
If I have CAT5 attached but have a Static address assigned to a different subnet than my router, I don't have your problem.

Where I would expect that problem would be if both eth0 and wlan0 are connected and have been assigned an IP address on the same subnet (even if there was no Gateway value for eth0)


Offline PeteyHall

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Re: FPP2.1 default route issue
« Reply #2 on: October 05, 2018, 09:05:01 AM »
I know it's not my network setup but here it is:
eth0 static - 192.168.80.2
mask 255's....
gateway blank
Ethernet plugged in directly to the f16v3


wlan0 static - 192.168.1.80
mask 255's...
gateway 192.168.1.1
wifi connected successfully
dns 8.8.8.8 (hardcoded)

Offline nmiller0113

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Re: FPP2.1 default route issue
« Reply #3 on: October 05, 2018, 11:13:00 AM »
A couple things.  Can you please specify the full mask as that is meaningful, and just to confirm it's not a typo is your eth0 network 192.168.80.2...just making sure you did indeed intend to have it on a different network....which is still yet to be confirmed it's on a different network without knowing your masks.  I was also curious, how are you confirming / determining that DNS lookup's are indeed going out of eth0?  Did you try unplugging eth0 instead of restarting the network service in the UI and seeing what happens then?  Also, and this is just for the sake of clarity in this conversation, DNS is not tied to any interface, it's a global setting for the entire operating system...you may have known that already but you listed it under wlan0 so I just wanted to make sure :)

Offline pixelpuppy

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Re: FPP2.1 default route issue
« Reply #4 on: October 05, 2018, 12:09:29 PM »
What version of FPP?   I recall a little while back there was an issue with the DNS client dying on reboot but could be restarted and work.  I forget the details, but its fixed in current version FPP V2.1   
I don't know if that's your issue, but the symptoms remind me of that previous issue.   
xLights and Vixen3 for sequencing / FPP for scheduling and playing / Falcon controllers for pixels / DIY controllers for everything else

Offline PeteyHall

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Re: FPP2.1 default route issue
« Reply #5 on: October 05, 2018, 01:56:11 PM »
What version of FPP?   I recall a little while back there was an issue with the DNS client dying on reboot but could be restarted and work.  I forget the details, but its fixed in current version FPP V2.1   
I don't know if that's your issue, but the symptoms remind me of that previous issue.   
Theyre both running 2.1.


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Offline PeteyHall

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Re: FPP2.1 default route issue
« Reply #6 on: October 05, 2018, 03:19:29 PM »
A couple things.  Can you please specify the full mask as that is meaningful, and just to confirm it's not a typo is your eth0 network 192.168.80.2...just making sure you did indeed intend to have it on a different network....which is still yet to be confirmed it's on a different network without knowing your masks.  I was also curious, how are you confirming / determining that DNS lookup's are indeed going out of eth0?  Did you try unplugging eth0 instead of restarting the network service in the UI and seeing what happens then?  Also, and this is just for the sake of clarity in this conversation, DNS is not tied to any interface, it's a global setting for the entire operating system...you may have known that already but you listed it under wlan0 so I just wanted to make sure :)

Here's the ifconfig output:
eth0: flags=-28605  mtu 1500
        inet 192.168.80.1  netmask 255.255.255.0  broadcast 192.168.80.255
        inet6 fe80::ba27:ebff:fe52:3207  prefixlen 64  scopeid 0x20
        ether b8:27:eb:52:32:07  txqueuelen 1000  (Ethernet)
        RX packets 8  bytes 500 (500.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 310  bytes 45108 (44.0 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 291  bytes 21976 (21.4 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 291  bytes 21976 (21.4 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

wlan0: flags=-28605  mtu 1500
        inet 192.168.1.80  netmask 255.255.255.0  broadcast 192.168.1.255
        inet6 fe80::ba27:ebff:fe07:6752  prefixlen 64  scopeid 0x20
        ether b8:27:eb:07:67:52  txqueuelen 1000  (Ethernet)
        RX packets 503  bytes 66006 (64.4 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 514  bytes 180333 (176.1 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

This was the exact same config I had running 1.9 and 2 beta without issue.  I only noticed the problem after upgrading to 2.0 as well and I thought a fix was going to be implemented but it doesn't seem to have been.

Yes, I understood the DNS is global, I just threw it under wlan0.

Offline PeteyHall

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Re: FPP2.1 default route issue
« Reply #7 on: October 05, 2018, 03:33:01 PM »
Think I may have found the issue, looks like the default route under 2.1 is getting set to eth0 even though there's no gateway assigned to it:
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface                                                                                           
default         0.0.0.0         0.0.0.0         U     0      0        0 eth0                               


Not sure why it's defaulting to eth0 (the f16v3's) when there's no gateway assigned to it.  So what I did was switch eth0 over to dhcp, rebooted, now my routing table looks like this:
default         192.168.1.1     0.0.0.0         UG    0      0        0 wlan0                                                                                           
google-public-d 192.168.1.1     255.255.255.255 UGH   0      0        0 wlan0                                                                                           
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 wlan0                                                                                           
192.168.1.1     0.0.0.0         255.255.255.255 UH    0      0        0 wlan0                                                                                           


I gave it about a minute then tried to get to Github, couldn't and when I went back in and pulled a route, it looked like it defaulted back to eth0:
Kernel IP routing table                                                                                                                                                 
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface                                                                                           
default         0.0.0.0         0.0.0.0         U     0      0        0 eth0                                                                                           
8.8.8.8         0.0.0.0         255.255.255.255 UH    0      0        0 eth0                                                                                           

so something in there is forcing eth0 to always be the default route - how do I stop that?  Thanks

Offline nmiller0113

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Re: FPP2.1 default route issue
« Reply #8 on: October 08, 2018, 09:36:46 AM »
Did you file a bug ticket on this to get fixed, or has anyone responded to you outside of this thread?

Offline lrhorer

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Re: FPP2.1 default route issue
« Reply #9 on: October 08, 2018, 12:01:43 PM »
That is indeed strange, and when I just checked, mine is doing pretty much the same thing:

Code: [Select]
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         192.168.8.1     0.0.0.0         UG    0      0        0 eth0
66.90.130.10    192.168.1.1     255.255.255.255 UGH   0      0        0 wlan0
66.90.130.10    192.168.8.1     255.255.255.255 UGH   0      0        0 eth0
66.90.130.101   192.168.1.1     255.255.255.255 UGH   0      0        0 wlan0
66.90.130.101   192.168.8.1     255.255.255.255 UGH   0      0        0 eth0
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 wlan0
192.168.1.1     0.0.0.0         255.255.255.255 UH    0      0        0 wlan0
192.168.8.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
192.168.8.1     0.0.0.0         255.255.255.255 UH    0      0        0 eth0


I deleted the default gateway and added a correct one:

Code: [Select]
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         192.168.1.1     0.0.0.0         UG    0      0        0 wlan0
66.90.130.10    192.168.1.1     255.255.255.255 UGH   0      0        0 wlan0
66.90.130.10    192.168.8.1     255.255.255.255 UGH   0      0        0 eth0
66.90.130.101   192.168.1.1     255.255.255.255 UGH   0      0        0 wlan0
66.90.130.101   192.168.8.1     255.255.255.255 UGH   0      0        0 eth0
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 wlan0
192.168.1.1     0.0.0.0         255.255.255.255 UH    0      0        0 wlan0
192.168.8.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
192.168.8.1     0.0.0.0         255.255.255.255 UH    0      0        0 eth0


Then I went in and cleaned up the table:

Code: [Select]
ernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         192.168.1.1     0.0.0.0         UG    0      0        0 wlan0
66.90.130.10    192.168.1.1     255.255.255.255 UGH   0      0        0 wlan0
66.90.130.101   192.168.1.1     255.255.255.255 UGH   0      0        0 wlan0
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 wlan0
192.168.1.1     0.0.0.0         255.255.255.255 UH    0      0        0 wlan0
192.168.8.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
192.168.8.1     0.0.0.0         255.255.255.255 UH    0      0        0 eth0

I then (once again!) had to update resolv.conf, because (yet again!) it had reverted to:

Code: [Select]
# Generated by Connection Manager
nameserver 127.0.0.1

At this point I can reach the internet.  After I rebooted, resolv.conf reverted, and the routes are once again screwed up:

Code: [Select]
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
default         192.168.1.1     0.0.0.0         UG    0      0        0 wlan0
66.90.130.10    192.168.1.1     255.255.255.255 UGH   0      0        0 wlan0
66.90.130.10    192.168.8.1     255.255.255.255 UGH   0      0        0 eth0
66.90.130.101   192.168.1.1     255.255.255.255 UGH   0      0        0 wlan0
66.90.130.101   192.168.8.1     255.255.255.255 UGH   0      0        0 eth0
192.168.1.0     0.0.0.0         255.255.255.0   U     0      0        0 wlan0
192.168.1.1     0.0.0.0         255.255.255.255 UH    0      0        0 wlan0
192.168.8.0     0.0.0.0         255.255.255.0   U     0      0        0 eth0
192.168.8.1     0.0.0.0         255.255.255.255 UH    0      0        0 eth0

There is definitely an issue, here.  How do we report a bug?
« Last Edit: October 08, 2018, 12:15:55 PM by lrhorer »

Offline aknflyer

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Re: FPP2.1 default route issue
« Reply #10 on: October 08, 2018, 11:52:02 PM »

Offline lrhorer

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Re: FPP2.1 default route issue
« Reply #11 on: October 10, 2018, 02:31:34 PM »
I reported bug# 426.

 

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