@Andone It was a Wan2 issue. for some reason it used the DNS of the other ISP and as a result it was blocked. I reconfigured the connection and for now the DNS issue stopped. If it happens again I...

@Andone When everything works ok the ping is low, when I have the issue the ping is the same but the nslookup doesn't work at all, saying host unreachable, as if something forces an other dns server...

Just installed a second DSL line on my ER5120 and I get DNS not found issues with my network, both wired and wireless. Windows troubleshooting sometimes correct the issue, other times doesn't with...