[thisiswater]

Hi everyone,

Apologies if I'm overlooking a simple solution here. This is my first time using dd-wrt, or any non preset router firmware. I have spent 10+ hours over the past few days trying to trouble shoot but haven't had much progress.

I'm using a linksys wrt1900acs V2, I've already successfully changed the firmware to ddwrt build 36247, first via updating the firmware with the factory-to-ddwrt.bin and then updated the firmware again using the ddwrt-linksys-wrt1900acsv2-webflash.bin file per the instructions I was following. All of this went relatively smoothly.

The router wasn't working however so I tried the following things,

1.) rebooting the router / modem

2.) enabling the mac address clone feature and changing the mac address to the one found on my old router. This seemed to help in the sense that the WAN-IP in the upper right hand corner of the page changed from 0.0.0.0 to 192.168.1.3 but still wasn't able to access the internet

3.) I changed my router IP to 192.168.1.3 next to match the WAN-IP I saw in the upper right, that didn't help, then I read there may be a IP conflict and changed it to 192.168.3.1, this didn't seem to help anything so I changed it back to 192.168.1.3

4.) I checked the channels on my old router, they were both set to auto but were using channels 6 and 149 respectively so I tried changing the channels in my new router from auto to 6 and 149. That didn't work so I changed them back to auto.

5.) I got my old router hooked up and working and then plugged the new wrt1900acsV2 into one of the old routers switches, then connected my laptop and cell phone to the wrt1900acsV2 SSID - this was promising in that I was then able to

~ Send some messages on my mobile phone over that signal (although they were noticeably slow to send)

~ Almost open baidu.com on my laptop (a popular search engine in China I've been using to see if I'm connected to the internet). The page didn't open, but the tab did show the Chinese name for the search engine which I took as an indication that some information had successfully passed over the signal. I should add though that when I ping baidu.com in terminal, I get the “ping: sendto: No route to host” response

Also, the wifi indicator lights on the linksys wrt1900acsV2 router go from solid white to a super quick flashing. Thats probably not helpful but I thought I’d throw it out there.

I've attached some screenshots which will hopefully be of help for someone to identify what configuration is giving me trouble. Again, apologies if I'm making a very novice mistake here.

Thanks in advance to any wonderful person out there who takes a stab at trying to help me.

P.S. I'm living in China which is why I have the regulatory domain set to CHINA.

[thisiswater]

Here are the aforementioned screenshots.

[Zyxx]

Currently in a hurry, so first thing first:

Your firmware is rather old ~2018, please update it to a more recent one, like the one mentioned here:

https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=323435

Also your device is able to switch between partition.
An update to firmware is always flashed into opposite partition to ensure functionality.

See ubootenv get and set boot_part here:
https://forum.dd-wrt.com/phpBB2/viewtopic.php?t=311117

Using automode for wifi is a bad idea, please use fixed channels.

Wifi indicator are lit and start to flicker during data being send / received.

IP conflict might be the result of doubled IP adress in your network.
Usually a network mask is given as 255.255.255.0 for private use. In this case the usage of 192.168.1.1-192.168.1.254 is allowed (.0 and .255 are reserved for special purposes, not for regular use).
--> Changing to 192.168.3.1 set your device outside of the network used by your ISP hardware. I'd suppose to use 192.168.1.XYZ whereas XYZ is something between above mentioned borders and not in use by other devices.

Also had a view into combined.pdf --> your DHCP server does not propagate a DNS, try adding the adress of your modem / another one provided by your ISP.

Need to hurry, more later...

[SurprisedItWorks]

Great suggestions by Zyxx. The link Zyxx names for the ubootenv business should be your overall guide for getting off to a solid start. Those are our "Cliff Notes," and you should know them well.

First though, there is a router-specific issue. Look on the bottom of your router at the label there in upper right. I believe it is blue. In the upper right of that label is a model number. If it ends in V2, you have a WRT1900ACSv2. If it does not, you have a WRT1900ACSv1. The V2 designation appears nowhere else on the router or the box it comes in. You need to use the dd-wrt build specific to your version. The two versions are almost the same but differ in where one internal table (I forget which) is stored. When you post in the forum, always identify your router including the version number.

Also router specific: this router runs a little too hot and should have included a fan in its design but did not. I run six of them and now use a cheap USB fan (AC Infinity makes reasonable ones) on each to push air up through the case. Before I did that, two of the six ran for weeks or months just fine but then one day became strange, just hanging up or, in one case, booting into the other partition spontaneously. The GUI status page shows a CPU temp. Usually you are OK at 72C but maybe not OK at 75C with this model (I'm assuming the v2.) I find the USB2 port doesn't provide power unless dd-wrt's USB functions are enabled, but the USB1 port hiding inside the memory-card slot seem to always supply power, so I plug my fans in there.

As Zyxx suggested, you seem to have an IP address conflict. The common (but not absolutely universal) situation is that you'll be fine if your router IP differs from the WAN IP in the third component. If your WAN IP is coming up as 192.168.1.1, then a router IP of 192.168.3.1 should be fine. I noticed you tried that but abandoned it. Trouble is that you seem to have more than one issue, so when you get one thing write you give up on it and revert because a second problem is in your way.

Do not use auto for the channel. Zyxx is right.

Do use a build that is not super old. A really, really problem-free one to get started with on that particular router is 40009 from June 2019. If you get everything working on that one, you can upgrade from there later.

On the main GUI page, select a time zone at the bottom but leave the server field blank, at least for now. There is an internal default that will work fine, and sometimes trying to get too specific leads to issues.

You do not need to use both factory-to... and webflash.bin files in an initial flash. Use factory... only when you are doing the flash from the Linksys firmware. From dd-wrt always use the webflash file. The Cliff Notes will explain the two-partition setup. Never be tempted to try the 30/30/30 reset that some of the obsolete guides suggest. If you try it on a modern Linksys router, you are likely to really regret it.

The Wireless Network Mode in the Wireless tab matters, because the Linksys wifi software, the part dd-wrt cannot replace, has always been troublesome but particularly for certain mode choices. On 2.4 GHz I use NG-Mixed, and on 5 GHz I use AC/N-Mixed with no problem. Re other wifi settings, see https://wiki.dd-wrt.com/wiki/index.php/Atheros/ath_wireless_settings.

Like Zyxx I'm kind of on the run at the moment but figured a few of these items would get you started. Good luck to you!

[thisiswater]

Wow thank you both for all of this helpful information. I will spend some time going through it all and let you know how it goes in the next couple days.

Thanks again!

[thisiswater]

Zyxx and Surpriseditworks - your advice has been really helpful, I’ve come up with quite a few other questions but I think I’ll start with the ones relating to what you both seem to believe is the most urgent issue - updating my firmware build.

You mentioned my device is able to switch between partitions. I read about this previously, the thread you pointed me towards led me to some more research and I now understand that these commands are done through the DDWRT GUI under the administration > commands tab.

I understand that the ubootenv get boot_part should come back with the partition number I am currently using. Here is the actual results I’ve gotten from this command;

a_pEnv->crc = 4ac8a766
crc32 = 4ac8a766
2

I assume that means I’m currently in the second partition?

I also understand that I’m supposed to then run the command ubootenv set boot_part # (where # is the partition that I’m not currently using before updating to the firmware I’d like to install.

Is the reason for this that because its going to install the upgraded firmware in the partition I’m not using, so assuming I’m right and I’m currently in the second partition, if I run the command ubootenv set boot_part 1, then I’ll be switched to the first partition, thus when I flash to the newer firmware it will actually be flashing it to partition 2?

One more question...

My understanding is if the partition I’m updating is currently running DDWRT I should upgrade using the second firmware file of whatever build I’m updating to (ie not the factory-to-ddwrt.bin file). But if I’m upgrading to DDWRT from the stock linksys firmware, I should first upgrade tot he factory-to-ddwrt.bin file. Is this correct?


I’ve also read I should clear my browser history / caches before downloading the firmware files. I’ll make sure to do this too.

Thanks again for being so generous with your help, I imagine you are both quite busy - I’m not expecting a quick reply. Thanks thanks thanks!!!

[SurprisedItWorks]

[Zyxx]

you are right @thisiswater, also thank you @SurprisedItWorks for your extensive addition, appreciated!

I prefer to update using "waterfox" (a firefox derivate) in linux, mostly spending my time on Kubuntu 18.04 LTS.
Since DXVK, Proton etc. were introduced for gaming I scrapped Windows... but different topic.

Please have in mind:
Administration --> Commands isn't always very feasible, at least it sometimes refused to work on my devices.
Years ago I began to telnet -nowadays SSH- into my devices, like SuprisedItWorks stated. This ensures to always receive feedback from your device after entering a command.

The WRT1900ACS v2 is my "daily driver device" runs stable and fast, good choice of yours!

[thisiswater]

Really impressed how helpful and patient you are both being with me. I’m going to keep doing my homework and try to get as much done as I can and not bother you both too much.

Here are a few (I think) exciting updates,

1.) I did some reading - per your advice - on accessing my router via terminal, got that all setup and working - AWESOME.

2.) I successfully used those two ubootenv commands to upgrade my partition 2 to this build: DD-WRT v3.0-r40009 std (06/11/19) - AWESOME.

3.) I’ve updated the wireless network mode to AC/N Mixed for 5ghz and NG Mixed for 2.4ghz

4.) I’ve enabled NTP client and chosen the time zone Asia/Shanghai - but the Server IP/name field I’ve left blank.

5.) I’ve updated my channels from auto to specific channels that have been working on my old router

I went back to my old router that works to see if I could dig up any relevant information. I confirmed the old router IP is set to 192.168.31, I found the subnet mask was set to 255.255.255.255 and I found a couple DNS numbers. I then turned off my old router, and updated these settings on my wrt1900acsV2. The router IP and subnet mask seemed like straight forward changes for me to make, after some research I figured out the DNS numbers should be added as static DNS 1 and static DNS 2. I saved these settings and then applied the changes.

Then I turned my wrt1900acsV2 router off and unplugged both my router and modem before turning them both back on. But after everything was back on, I couldn’t connect to either signal (I was getting the ! Sign in my wifi signal indicator on my Mac) - my old router was still unplugged entirely.

I ended up reseting the router, once it was back on it was a little bit of a nuisance to reconfigure everything* but I was thrilled that I still had ddwrt and was still in the v3.0-r40009 std (06/11/19) build.

*I reconfigured it back to the way it was before I changed the configurations for router IP, subnet mask, and static DNS.

But then I encountered this problem when I tried to make the ssh connection via terminal;

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
SHA256:[fingerprint]
Please contact your system administrator.
Add correct host key in /Users/sam/.ssh/known_hosts to get rid of this message.
Offending RSA key in /Users/sam/.ssh/known_hosts:1
RSA host key for 192.168.1.1 has changed and you have requested strict checking.
Host key verification failed.

I managed to “fix” this by using this command to remove the offending key from my known_hosts file, ssh-keygen -R 192.168.1.1 and saying yes I want to continue.

I figured this error must have been a result of me reseting my router as opposed to some malicious activity, was that a dangerous assumption to make?

@Zyxx - you mentioned my DHCP server does not propagate a DNS server? Could you explain where you noticed that and how I can go about adding the address of my modem? Where is that configuration made? (I found a DNS address using my old server, I can try to use that if I can figure out where to configure it.

@Surpriseditworks - btw - I totally agree, my testing has been very flawed thus far since its unlikely / impossible that changing a single setting is going to be enough.

I do feel like I’m making some progress, or at the very least learning more about routers.

One more thing, I also noticed that my old router uses PPPOE, should I enable that in my wrt1900acsV2 as well?

Let me know if there are any configuration pages that it would be helpful to see screenshots of to help me troubleshoot further. I’m moving tomorrow so it will be a few days before I have a new internet connection to test changes I’ve made.

Again, really really really appreciate all the help. I would be so thrilled to get this beast working

[SurprisedItWorks]

[Zyxx]

[wrt1200ac_repair]

Check main power filter cap by dc power jack. If its faulty replace with 25v 470uf.

[thisiswater]

Hi @surpriseditworks and @zyxx,

Just arrived in the new city a couple days ago and have been pretty preoccupied with getting settled.

@zyxx - I should have been more clear about this previously, yes my setup has always been

setup 1: ISP's modem ------> "old" router

OR

setup 2: ISP's modems ------> new wrt1900acsV2

I use both (although not simultaneously) because I need to have a router that is functional when I need to get work done or do more research on changes to make to the wrt1900acsV2.

When I switch from setup 1 to setup 2 I always unplug both the modem and the router and then plug back in the modem and connect it to the router I want to use and power that on as well (I never have two routers on at once).

Okay here are few other updates / questions, as per my subject line, get to start over with a fresh internet connection. Hope this one is easier to setup my router on

1.) I have a new 500M internet connection, I tried to work with the guy that installed it on getting my wrt1900acsV2 setup. He had me choose PPOE instead of DHCP and entered a username password from the ISP (which I still have should it become necessary), He was expecting that to reassign the router IP after we hit apply settings, but when it didn't. He pretty much just gave up.

2.) I notice now though that on the router that the ISP provided, it seems to have a connection type as DHCP - not PPOE. So I'm gonna try and stick with DHCP on the wrt1900acsV2 as well for now.

3.) When I plugged in my router to the new modem, my router SSID seemed to be reset back to the default dd-wrt and all my previously saved settings were also gone. But no big deal, I'm getting more comfortable at setting all the basics, did a channel scan and got the best channels for my new spot as well.

4.) I noticed when I tried to connect via ssh in terminal I got that same warning message as before. I have a couple questions about this,

* You said, "Removing the corresponding key from known_hosts is all it takes to fix it" I had previously read about this but could not figure out what the corresponding key is (all terminal spits out is a fingerprint) OR how I would go about removing it even if I did figure out where to find it.

* You also said, "Running ssh-keygen again is not needed at all and will force you to re-enter a new public key in the sshd section of the dd-wrt GUI." - I've tried to find more on this and used control F to try and find anywhere in the dd-wrt GUi that has SSH, but couldn't find anywhere that woul dallow me to enter a new public key.

I'm in no hurry on this - nothing I need to do in terminal at the moment. I I'll continue to look this up as well.

5.) When I plug in the wrt1900acsV2 into the new modem and access the ddwrt GUI I notice that my WAN IP is now 192.168.1.2

6.) I didn't go back and enable mac address cloning, I'm going to try and leave that disabled unless you think its going to be helpful (the ISP guy suggested I leave it off, for whatever thats worth).

7.) I've included some screenshots of the current configurations - let me know if you see anything that pops out that I should try to investigate further.

Thanks again for offering so much help here. Hugely appreciated

[SurprisedItWorks]

[thisiswater]

Okay, so I've set my router IP to 192.168.X.1 (I tried X=2, and then when that didn't work, I tried a few others, I've now reverted back to 192.168.2.1 for the time being). Still unable to connect to the internet though with this router

I'll keep filtering through my configurations and searching online, hopefully I can get this thing working

Yeah, I hear ya on the over heating router, I've ordered a USB fan already but it hasn't arrived yet. I've been keeping the router turned off when I am not tinkering it with it until then. Also, I still seem to be in boot_part 2, so it appears I didn't get swapped over to the other partition.

I will figure out the known hosts and key issues later today so I can continue to use terminal to connect via ssh.


Thanks again!