Router can ping sites; clients cannot

[XIII]

Had a weird problem at a family member today (AC68U, Asuswrt-Merlin 384.4_2). While the router could successfully ping sites all clients (wireless and wired) could not: all requests timed out (nslookup worked fine for both the router and the clients). Disabling AB-Solution, SkyNet, and even the router’s own firewall (including several reboots) did not help. Restoring saved settings from a month ago did not help either. Only when I restored the jffs contents from a month ago (without formatting the jffs partition) clients could finally ping (and visit) sites.

What might have been wrong?

How can I investigate this next time? (Spent a lot of time without any luck)

 

[XIII]

Same problem on another family member’s router (AC56U, 384.4_2)!

I’m not at their house and remote ssh/mosh is not working, so I’m fairly limited in what I can try...

Any tips?

 

[XIII]

Removing the (Entware) flash drive, disabling the JFFS custom scripts/configs, and rebooting the router restored basic internet access.

In fact I can now ssh into the router again.

Going to check the logs later today.

 

[XIII]

At least one suspicious entry:

Feb 14 01:00:16 kernel: JFFS2 notice: (153) check_node_data: wrong data CRC in data node at 0x028050e0: read 0x410a5138, calculated 0xa50fd879.

Seems like the JFFS partition need to be reformatted?

(Wonder whether the same issue was present on the AC68U - unfortunately I did not copy logs this weekend)

Hope this does not mean that the flash is written too many times...

 

[RMerlin]

Hope this does not mean that the flash is written too many times...

It will be years before anyone reaches that point.

 

[XIII]

It will be years before anyone reaches that point.

So a format might solve this? Or does it indicate a rare hardware error?

 

[RMerlin]

So a format might solve this? Or does it indicate a rare hardware error?

Format should do.

I have one or two of my development device with a similar error, and personally I simply ignore them.

 

[XIII]

Formatted and restored older jffs & backups. Everything seemed fine.

Then I updated amtm, AB-Solution, and SkyNet to the most recent versions. Same problem again...

Tried 384.5 alpha 3 instead of 384.4_2. Problem remained.

Downgraded to 384.4_2 and did everything one more time. Seems to be working now, but for how long?

And still no clue what's wrong when it happens...

 

[XIII]

That was the AC56U (yesterday). As of this morning the AC68U from the original post is having the problem as well (again).

Have no clue how to investigate this... Anyone?

(Would it matter that my own router is on 192.168.1.1 and these two are on 192.168.2.1 and 192.168.3.1? - in different networks)