I have a wrt1900acs and I'm trying to connect it behind a comcast cable modem. The overview shows the following version installed ... "Powered by LuCI lede-17.01 branch (git-17.152.82987-7f6fc16) / LEDE Reboot 17.01.2 r3435-65eec8bd5f"

However, it's not grabbing an IP on the wan interfaces. Anyone have thoughts as to why? Here is my /etc/config/network.

$ cat network

config interface 'loopback'
        option ifname 'lo'
        option proto 'static'
        option ipaddr '127.0.0.1'
        option netmask '255.0.0.0'

config globals 'globals'
        option ula_prefix 'fe5c:182c:a4b4::/48'

config interface 'lan'
        option type 'bridge'
        option ifname 'eth0'
        option proto 'static'
        option netmask '255.255.255.0'
        option ip6assign '60'
        option ipaddr '192.168.10.1'
        option broadcast '192.168.10.255'
        option dns '209.222.18.222 209.222.18.218'

config interface 'wan'
        option ifname 'eth1'
        option _orig_ifname 'eth1'
        option _orig_bridge 'false'
        option proto 'dhcp'

config interface 'wan6'
        option ifname 'eth1'
        option proto 'dhcpv6'
        option reqprefix 'auto'
        option reqaddress 'try'

config switch
        option name 'switch0'
        option reset '1'
        option enable_vlan '1'

config switch_vlan
        option device 'switch0'
        option vlan '1'
        option ports '0 1 2 3 5'

config switch_vlan
        option device 'switch0'
        option vlan '2'
        option ports '4 6'

config interface 'TUN0'
        option proto 'none'
        option ifname 'tun0'
        option auto '1'

Anyhelp much appreciated.

You installed LEDE, perhaps you should ask in the LEDE forums, instead of the OpenWrt forums.
Have you used another router with that modem? How was it configured?
Please, post your logs here.

is the comcast set to bridge mode?

have you rebooted the comcast device?

Apparently the SB6121 is a straight through modem so there is no config for setting it in bridge mode. I have rebooted the device, but to no avail.

(Last edited by langly on 9 Dec 2017, 03:20)

I was using a Cisco ASA, but the device was apparently engineered to only last for 14 months and Cisco won't back their own products (yes, they put out a FN saying it will die in about 18 months). I'm done with them. But it was configured via DHCP and worked fine (for the time it did work).

I keep hearing LEDE is merging w/ OWRT, and OWRT doesn't offer anything for the wrt1900acs, and one came from the other anyways ... I don't know, I'm confused. Not that I ever wanted anything to do w/ LEDE any ways. Figured they can't be that different (for this issue) in such a short amount of time. But I will go to the dark side if I have to.

(Last edited by langly on 9 Dec 2017, 03:28)

lede is where you need to be for 1900acs and i can confirm dhcp on wan works fine on it

Though you may want to give this version a whirl:

https://davidc502sis.dynamic-dns.net/

I think there is an issue with your vlan setup.  try to get it working without the vlan first.

(Last edited by WWTK on 9 Dec 2017, 17:33)