This is my first post, so if I need to do anything different, let me know!

My Internet does not work on my default mac address when I boot up my Linux server. It doesn't get assigned an ipv4 address. However, when I change/spoof my mac address, and restart some networking services, refresh my dhclient (if thats the right wording), everything seems to just work fine and i'm assigned a ipv4.

I checked my router settings, my mac address is not blocked.

Here's my ifconfig before i change my mac:
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet6 fe80::3a01:97ff:fe1f:f10f prefixlen 64 scopeid 0x20<link>
ether 38:01:97:1f:f1:0f txqueuelen 1000 (Ethernet)
RX packets 33334 bytes 24530337 (23.3 MiB)
RX errors 0 dropped 1 overruns 0 frame 0
TX packets 25008 bytes 7507766 (7.1 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
after:
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.1.88 netmask 255.255.255.0 broadcast 192.168.1.255
inet6 2602:30a:c7ed:e280:7926:12c:4ee8:f66 prefixlen 64 scopeid 0x0<global>
inet6 2602:30a:c7ed:e280:3a01:97ff:fe1f:f10f prefixlen 64 scopeid 0x0<global>
inet6 fe80::3a01:97ff:fe1f:f10f prefixlen 64 scopeid 0x20<link>
ether 38:01:97:1f:f1:0f txqueuelen 1000 (Ethernet)
RX packets 33491 bytes 24576888 (23.4 MiB)
RX errors 0 dropped 1 overruns 0 frame 0
TX packets 25099 bytes 7535002 (7.1 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

Had a similar issue when I upgraded the distro a while back but was because of macchanger. The macchanger upgrade would automatically changed my mac address at boot even though I told it not to.



Make sure your mac is back to its original permanent with:

# ifconfig eth0 down
# macchanger -P eth0
# ifconfig eth0 up

Then can go into the interfaces file and see what mac address is set for eth0 or can go into the Network Manager / Wired Settings and re-enter the original mac address for eth0

Double check your router to make sure its the same mac if you have mac filtering

Then can restart networking to see if it resorts back again with:

# /etc/init.d/networking restart

In first instance you can see there is no ipv4 and then it is on second. I'd look to why you are not getting an assignment.
Are you using ipv6? Does router fully support it? Is fqdn translations returned in ipv4?