I’ve been attempting to connect a Pi 4B 4Gb to a network on a Technicolor DGA4231 router in the latest Raspberry Pi OS. Flashed to a Micro SD card with no modifications at all.
It seems to get an incorrect route assigned from the router and also an incorrect DNS. Both are set to a 192.168.1.140 IP which doesn’t exist at all on the network.
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.1.140 0.0.0.0 UG 303 0 0 wlan0
169.254.0.0 0.0.0.0 255.255.0.0 U 202 0 0 eth0
192.168.1.0 0.0.0.0 255.255.255.0 U 303 0 0 wlan0
Here’s the result of ‘ifconfig’ (when connecting via wifi):
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 169.254.22.45 netmask 255.255.0.0 broadcast 169.254.255.255
inet6 fe80::9074:5f6b:aeb1:1e67 prefixlen 64 scopeid 0x20<link>
ether dc:a6:32:dd:ab:10 txqueuelen 1000 (Ethernet)
RX packets 229 bytes 164902 (161.0 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 4 bytes 690 (690.0 B)
TX errors 629 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 109 bytes 11500 (11.2 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 109 bytes 11500 (11.2 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
wlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.104 netmask 255.255.255.0 broadcast 192.168.1.255
inet6 fe80::c84a:e40a:a726:3007 prefixlen 64 scopeid 0x20<link>
ether dc:a6:32:dd:ab:11 txqueuelen 1000 (Ethernet)
RX packets 6161 bytes 6357121 (6.0 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 4508 bytes 541311 (528.6 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
Pinging the router at 192.168.1.1 gives ‘destination host unreachable’. It does this on both ethernet and wifi. DNS doesn't work either.
I added a new default route as follows:
route add default gw 192.168.1.1 eth0
But it didn’t help.
I attempted to make the Pi use a static ip, suspecting DHCP issues, using the following setup in /etc/dhcpcd.conf:
# Example static IP configuration:
nohook lookup-hostname
interface eth0
static ip_address=192.168.1.23/24
static ip6_address=fd51:42f8:caae:d92e::ff/64
static routers=192.168.1.1
static domain_name_servers=192.168.1.1 8.8.8.8 fd51:42f8:caae:d92e::1
I also set up a static IP reservation on the router by mac address.
This successfully shows the correct static IP, route, and DNS are set when looking at ‘route -n’ and ‘ifconfig’. However, I still cannot ping the router or anything on the internet. DNS doesn’t work either.
The strangest thing is that if I create a wifi hotspot from my Android phone, the Pi 4 B connects perfectly and everything works including full internet access.
But connecting to the home network via wifi or wired causes the issues described. What could be the issue?
I've rebooted everything multiple times.
Many thanks in advance for any ideas!
I disabled ipv6 as a last ditch attempt. I've now discovered it does occasionally connect to the internet successfully! About one in three reboots I get a perfect connection that runs well. Then after another reboot it is dead. This is with the static IP config I posted above, but on wlan0.
I'm even more confused now! (also, great username you have there)
– neilmillstone Apr 25 '21 at 00:53