MikeL's ActionTec C 1900 modem HowTo

Last Sunday I made a bad configuration change to my C3000Z, and it would not connect, even with a factory reset. I called Centurylink, and they found some other customers name on my account, and said sorry, call the Solutions Dept. on Monday. Needless to say, I was furious. Called Solutions Dept. on Monday, got someone with a brain, and we determined it was probably the modem had croaked - they're sending me a new one. In the interim, I was able to borrow an older C1900 (in fact it's my old documented below, borrowed back from a guy I'd leant it to when his croaked.)

So I'm trying to get the C1900 back to operational, and am documenting the complete steps, as I'll need to follow them again in the next few days when the replacement C3000Z arrives.

WAN settings as below 16-Nov.
  PP Auto: ena
  No PP: dis
  Block of static
  gateway: (provided)
  lan dhcp: Private LAN subnet
  static dns:
  pri: (provided)
  sec: (provided)

DHCP settings:
  dhcp: enabled
  modem ip:
  begin ip:
  end ip:
  lease time: (default)
  dns type: default

IP v4 Firewall:
  Create rule, do this for each of the following, select TCP & UDP:
  drvwymon: drvwymon, 23256
  named: zone xfer, 53
  cwop: Cumuluscwop, 14580
Then select All Public, and ensure that all the following allow both in and out:
  ftp, ftps, http, https, drvwymon, named, cwop

Been running a Zyxel C3000Z dual DSL modem now for several years, too lazy to make a new page for it.
I've had to do some firewall changes. Set to "All Public" and "Low". Add the following:
drvwymon tcp 23256 tcp (my drvwymon program)
RTC-Discord chat 50000-65536 udp (Ellis' online chat app)
Cumulus/CWOP tcp 14580 tcp (Cumulus software)
named zone xfr tcp 53 tcp (named zone transfer)


I have QWest/CenturyLink Dual DSL, using an ActionTec C 1900 modem. I've had a heck of a time getting it set up for a fairly simple configuration. I'll jot a few notes here about what I had to settle for.

The goal was to have DHCP turned on for the inside LAN; any computer plugged into it, or any computer using wireless would simply be allocated a protected internal IP address.

The exception is that there are several servers that need to be available to the outside world.

I have a block of static IP addresses from CenturyLink. When you get this, you are actually allocated a block of 8 (hence the .248 subnet mask), however only 5 are available to you for use.

Here's what got it working:

Now the internal computers:
One last word of caution. The builtin firewall in the modem may get in the way of your servers activity. If you suspect this is the problem (data not making it into your server), try moving the server into a DMZ (advenced setting). If this fixes it, you've got a modem firewall issue.

I have a tricky system that uses one of these servers to do SMS messages with cellphones. This is implemented via HTTP (normal looking web requests via port 80). The factory default setting of this modem is for FIREWALL ENABLED, at LOW security. Note that this setting allows web requests (port 80), outgoing, BUT NOT INCOMING. I had to go into the firewall configuration screen and select port 80 incoming - this is true for you if you're running a web server.

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