The Ocean City release was intended to be an massive release, fixing all known bugs and implementing all desired features. Our desire exceeded our reach, and we chose to pursue significantly scaled back (but still important) goals described elsewhere. These documents - devoted to the Ocean City release - are now obsolete:


How CeroWrt is different from OpenWrt

Our goal is to build more of a test tool for the internet edge than a home router - although it can be used as such. We encourage you to install the software on a spare router before committing to using it day to day - and compare it against your existing router.

The Onboard documentation has far more detail as to what’s in the software.

Major differences between OpenWrt and CeroWrt - all interfaces are routed, not bridged, there is a full blown dns server, and the ip address scheme and device naming scheme differ significantly from what you may be used to.

Aside from that, most of the core stuff in CeroWrt is now in OpenWrt.

Core things you should know

Default Password

The router has a default, rather than empty, password.

login: root
password: Beatthebloat

Do change it on installation, and even better, put your ssh key on it and disable password access entirely.

IP addresses & DNS

CeroWrt is a test platform, and as such we wanted it to co-exist within existing networks as best as possible, without conflicting with an existing network, and to not require NAT in order to function inside that network. NAT skews some test results horribly.

Since there is no public IP address space left, 10 networks are being increasingly used as backbone networks, and 192.168.X is most likely a number you are already using on your existing network, we chose the range to play in. The default address for the router is Each of the interfaces has a /27 subnet from this range by default - this allows 30 addresses per interface, a sensible limit for home/edge routers.

It is ironic that this is the last piece of ‘free’ IP address space left. See also BANA.

If you find this IP hard to remember or type, dns is enabled by default for a virtual subdomain of ‘home.lan. You should be able to get to it via gw.home.lan if you get dhcp from the router. Changing the default ip address ranges is difficult to do via the web interface and we suggest you stick with it for a while until you understand the reasoning, firewall, routing, and naming rules. (See DNS note below).

If you are running this inside your network, and not as your default gw, configure your default gw to statically assign an ip address, and route your subnet to the CeroWrt router, and turn off NAT.

Device/Interface Naming

We use an unusual device naming scheme to manage multiple kinds of wireless devices. Instead of using eth0, eth1, etc. the interfaces have names that more accurately reflect their actual use. Prefixes use Wireless vs. Ethernet and Secure, Guest/Gateway, or DMZ. As noted above, each of these interfaces has a /27 subnet assigned. Thus:

  • ge00 is the gateway ethernet;
  • se00 is the first LAN ethernet interface;
  • sw00 is the first secure wireless interface at 2.4GHz;
  • gw10 is a guest wireless interface at 5.x GHz;
  • etc.

IPv6 is enabled BY DEFAULT.

If - when connected to a real ip address on a gw, it doesn’t ‘just work’, we want to know about it.


The bind9 DNS installation is as hardened as possible, running in a chroot jail, respawning from xinetd. (but see DNS note below).

Multiple services are enabled ‘in’ by default, notably http, https, ssh, & rsync. DNS allows in the entire 2002 address range into the ‘us’ DNS view, this should be restricted to just your 200248 lan.

From here, please move on to the download and installation guide.

NB re: DNS

The bind/DNS code of recent builds of CeroWrt (e.g., bql and rc8 builds) is not functional. For example, these builds do not support the *.home.lan dns names.

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