How to enable NAT Loopback on ZyXEL C1000Z router?

[Deozaan]

Hi folks,

I recently got a new ZyXEL C1000Z DSL router (provided by my new ISP--I didn't get a choice) which unfortunately doesn't have NAT Loopback^w enabled by default. Through some Googling I've found reports that it is possible to enable NAT Loopback on the router, but so far I've failed to find any instructions that actually work. Can any of you fine folks with better Googlefu skills than me find a solution?

The reason why I want this feature enabled is so that I can use a service such as DynDNS to automatically update my IP address, then I can just type something like MyIP.dyndns.com to get my IP from anywhere. This is also helpful to connect to my own computer even on my LAN for multiplayer games--but this where the IP loopback is required. With it disabled, the router does not allow MyIP.dyndns.com to resolve to the router's (ISP's) IP address.

Any help or suggestions?

Thanks!

[4wd]

On my old Zyxel P660 you had to telnet into the router and enter: ip nat loopback on

This is only saved until the router reboots, so you have to edit a file, (whose name escapes me atm), to have it done at every power on.  I'll check through my old files and see if I can dig the filename out.

Here we go: autoexec.net

sys edit autoexec.net

And add the ip nat loopback on to the end of it.

Of course, if your ISP hasn't given you the password to access telnet, or disabled it somehow - you're screwed.

[Deozaan]

Thanks. I've seen similar instructions before, but they don't seem to work on the C1000Z.

Here's what I get:

[attachimg=#]

Here are some more links (thanks Lanux128!) with similar instructions which also don't seem to help me. )c:

http://diary.piku.org.uk/2009/04/17/port-forwarding-and-nat-loopback-on-a-zyxel-adsl-router/
http://www.midknightmagic.com/index.php/how-to-turn-on-nat-loopback-on-zyxel-zywall/
http://aumja24-usa.blogspot.com/2010/10/p-660hw-t1-how-to-set-loopback-in-adsl.html
http://sysadminsgrove.blogspot.com/2007/08/zyxel-nat-loopback-and-dyndns-in-lan.html

[app103]

You might be interested in this: https://qwest.centurylink.com/internethelp/modem-c1000z-adv-dynamic-dns.html

[app103]

Here's another page that might help: http://opensimulator.org/wiki/Network_Settings#Local_connections_with_ZyXEL_DSL_modem.2Frouter_and_NAT.2FPort_Forwarding

[Deozaan]

You might be interested in this: https://qwest.centurylink.com/internethelp/modem-c1000z-adv-dynamic-dns.html

I think this just updates the IP address with my DynDNS account (which I already use the Dyn Updater client to do).

Here's another page that might help: http://opensimulator.org/wiki/Network_Settings#Local_connections_with_ZyXEL_DSL_modem.2Frouter_and_NAT.2FPort_Forwarding

This gives me instructions for the ZyXEL Prestige 660ME-61 DSL Router. Mine is a ZyXEL C1000Z DSL Router. When I telnet into the router, I don't get a menu like those pictures show. I get what I showed in the picture above.

Thanks for the attempts, though. (c:

[4wd]

Problem is your Zyxel C1000Z appears to be an ISP specific, (as in appearance/firmware), incarnation of one of the normal Zyxel VDSL2 modem/routers - so who knows what CenturyLink may or may not have incorporated into it.

Any chance of doing an FCC ID search, it may give us the real model.

Have you tried typing help at the telnet prompt ?  Who knows it may spit out a list of commands.

BTW, won't your games take an IP address to connect to, (in which case you could use the LAN IP) ?

[Deozaan]

Any chance of doing an FCC ID search, it may give us the real model.

Um... Does this help at all? I have no idea what I'm looking for in there.

FCC ID: I88C1000Z

https://apps.fcc.gov/tcb/GetTcb731Report.do?applicationId=250650&fcc_id=I88C1000Z

I did notice another brand/number on the label:

MitraStar WUXI-002

Which after Googling, led to this:

http://wikidevi.com/wiki/ZyXEL_PK5001Z_(CenturyLink)

Which led to this:

http://wikidevi.com/wiki/ZyXEL_C1000Z

Which says this: aka DSL-410GNU-B1B v2

Which is a dead end for me. Googling for DSL-410GNU-B1B v2 just links me back to that same webpage.

Have you tried typing help at the telnet prompt ?  Who knows it may spit out a list of commands.

Yep. But I'm not sure which one, if any, will do what I'm trying to do.

[attachthumb=#]

[4wd]

FCC ID: I88C1000Z

https://apps.fcc.gov/tcb/GetTcb731Report.do?applicationId=250650&fcc_id=I88C1000Z

Looks like they actually came up with a new model for CenturyLink, rather than rebadging one of their existing models.

Going by the pictures at CenturyLink, the Zyxel VMG1312-B series might be the closest Zyxel standard model.

A bit of searching has failed to find anything for that re. loopback.

Have you tried typing help at the telnet prompt ?  Who knows it may spit out a list of commands.

Yep. But I'm not sure which one, if any, will do what I'm trying to do.
(see attachment in previous post)

Well, there aren't that many - if you leave out the obviously nothing to do with it ones, (eg. reboot, loglevel, dumpsysinfo, etc), and try getting the extras functions of the other commands, one of their parameters may be relevant.

eg.

wan help

About the only thing I can think of trying without fluking it in a search.  Sorry I can't be more help.

Just as an aside, the ActionTec C1000A, (supposedly also used by CenturyLink), has been reported as having no NAT loopback in an Amazon review.  The same may apply to the Zyxel.

[Stoic Joker]

Common guys, think like a hacker... run the dumpsys & dumpcfg (to get a list of all the available settings and their values), look for the setting that you need changed, and then Google that specific setting. The specific router isn't as important as the OS that runs on it...because that's what you're interacting with.

[4wd]

Well there's a big DOH! moment 

[Deozaan]

Does it never end? I ran dumpsysinfo and it really is dumping! Screen after screen of gobbledegook (it's all Greek to me!) and it just never ends. The command still hasn't finished yet.

I wish I could put DD-WRT on this thing.

[Stoic Joker]

Might as well cancel it. The screen buffer isn't that big so it'll only have the last 320 lines of the dump when it finishes.

Try either | or > filename to see if you can dump it to a file.

Also try the dumpcfg (Dump Configuration) command first as it's most likely the one you're after (I'm guessing the other is a binary dump of the firmware).

[4wd]

Might as well cancel it. The screen buffer isn't that big so it'll only have the last 320 lines of the dump when it finishes.

Turn on PuTTY's logging 

[bradleonard]

For those of you who actually got into the telnet settings of your C1000Z what did you figure out your login and password was?

I tried the admin pw that is printed on the label on the bottom but that isn't it. I also tried the password that I changed the router admin account too. It of course didn't work. Anybody have something that works?

[bradleonard]

So I turned on remote console in the configuration page an am now up to speed with where everyone else is at. They've got a specfic firmware on this model that doesn't seem to give us this capability.

[Deozaan]

They've got a specfic firmware on this model that doesn't seem to give us this capability.

Yeah, sadly I've given up hope on this. )c:

[bradleonard]

Yes, it does seem hopeless. Since they are providing the modem it is locked down in their favor.

[app103]

Have you guys considered bridging it out and using your own router with it? Might just solve all your problems. 

[Deozaan]

Have you guys considered bridging it out and using your own router with it? Might just solve all your problems. 

You mean like using my own router as a repeater? I'm not sure that would solve the problem since the ZyXEL would be the "outermost" part of the firewall, and the NAT Loopback still wouldn't work at that level. But to be honest, I'm not entirely sure how these things work.

[app103]

No, I mean switching it so it acts as only a modem and not as a router at all.

http://www.akadia.com/services/zyxel_transparent_mode.html

[4wd]

I'm not sure that would solve the problem since the ZyXEL would be the "outermost" part of the firewall, and the NAT Loopback still wouldn't work at that level. But to be honest, I'm not entirely sure how these things work.

That's how my setup is, my router, (ASUS RT-N16), does all logging into the ADSL and the loopback.  The modem/router, (TP-Link TD-8817), is switched to Bridge mode - it's a transparent connection to the ISP as far as the RT-N16 is concerned.

I must be getting old to have forgotten that 

[Deozaan]

No, I mean switching it so it acts as only a modem and not as a router at all.

http://www.akadia.com/services/zyxel_transparent_mode.html

I'm not sure that would solve the problem since the ZyXEL would be the "outermost" part of the firewall, and the NAT Loopback still wouldn't work at that level. But to be honest, I'm not entirely sure how these things work.

That's how my setup is, my router, (ASUS RT-N16), does all logging into the ADSL and the loopback.  The modem/router, (TP-Link TD-8817), is switched to Bridge mode - it's a transparent connection to the ISP as far as the RT-N16 is concerned.

That sounds like an awesome solution, since I already have my router configured with ports forwarded and all that, it would be nice to use it without having to reconfigure all those little tweaks I've made over the years. I'll give that a try and report back.