strange IP address in all my routes & Red WAN light on router

[TanyaC]

A few weeks ago (I don't know if it coincides with a failed attempt at upgrading my RT-AC88u firmware), I've been seeing a strange IP address in my routes when not using a VPN.

I successfully upgrade to 384.7.2 on Sunday

The VPN is run via the OpenVPN software on the clients. There is no router configuration for VPN because some clients do not use the VPN. So it's just the OpenVPN software with a configuration file provided by the VPN company.

The WAN light is solid red. I only noticed this 24 hours ago. It may have started when I upgraded but I don't think so. I walk past the router everytime I go downstairs so I would have noticed it if it was on earlier. However, the internet is connected fine. I am getting typical up/down speeds.

The NTD has all green lights. No issues there.

Now, here;s a typical route...
You can see the 10.20.21.13 address as the second hop.

C:\Users\Tanya>tracert www.yahoo.com

Tracing route to atsv2-fp-shed.wg1.b.yahoo.com [106.10.250.11]
over a maximum of 30 hops:

1 <1 ms <1 ms <1 ms router.asus.com [192.168.1.254]
2 2 ms 2 ms 1 ms 10.20.21.13
3 2 ms 2 ms 2 ms nme-apt-bur-wgw1-be-10.tpgi.com.au [203.219.155.138]
4 2 ms 2 ms 2 ms 203-219-107-206.static.tpgi.com.au [203.219.107.206]
5 2 ms 2 ms 3 ms Bundle-Ether-13.win-edge901.melbourne.telstra.net [165.228.52.1]
6 3 ms 3 ms 3 ms bundle-ether11.win-core10.melbourne.telstra.net [203.50.11.107]
7 15 ms 16 ms 16 ms bundle-ether12.ken-core10.sydney.telstra.net [203.50.11.122]
8 16 ms 16 ms 16 ms bundle-ether1.oxf-gw10.sydney.telstra.net [203.50.6.97]
9 16 ms 16 ms 16 ms bundle-ether1.sydo-core04.sydney.reach.com [203.50.13.94]
10 15 ms 16 ms 16 ms i-0-1-0-46.sydo-core03.bi.telstraglobal.net [202.84.222.57]
11 130 ms 130 ms 130 ms i-15203.hkth-core02.telstraglobal.net [202.84.138.41]
12 157 ms 157 ms 158 ms i-15152.sgcn-core01.telstraglobal.net [202.84.141.109]
13 158 ms 157 ms 157 ms i-91.istt04.telstraglobal.net [202.84.224.197]
14 157 ms 157 ms 157 ms unknown.telstraglobal.net [202.126.129.139]
15 157 ms 158 ms 158 ms ae-4.msr1.sg3.yahoo.com [203.84.209.75]
16 157 ms 158 ms 158 ms ae-2.clr1-a-gdc.sg3.yahoo.com [106.10.128.3]
17 158 ms 157 ms 158 ms et-17-9.bas1-1-flk.sg3.yahoo.com [106.10.128.29]
18 158 ms 158 ms 158 ms media-router-fp2.prod1.media.vip.sg3.yahoo.com [106.10.250.11]

Trace complete.

My ISP is blaming my router. Could it be?

 

[ColinTaylor]

The 10.20.21.13 address is one of the routers on your ISP's internal network. That's perfectly normal.

 

[TanyaC]

The 10.20.21.13 address is one of the routers on your ISP's internal network. That's perfectly normal.

Wow. Ok, In 2 decades I've never seen a private non-routable address used in by an ISP. I must have led a very sheltered life
Why then would they blame my router as being the cause?

Any ideas on why the red light is on if everything seems to be working?

 

[TanyaC]

When the LAN DNS servers are removed the router reports the WAN link is down (Red light comes on). When DNS servers are specified on the LAN page, the red light goes off.

Does that mean that I have something else configured wrong (DNSSEC = No, Forward to upstream = No, Advertise = Yes)?

 

[ADFHogan]

Not the first time I've seen Westnet/iiNet/TPG have a 10/8 IP in a traceroute

As for red light.. it sounds like the method that the router uses to check for internet connectivity doesn't work without DNS available on the router (I think it tries to connect to an Asus address to prove it can reach the internet), so if there's no DNS present, it might be failing the internet check.. I vaaaaaguely recall there being some way of overriding/working around this, but can't be sure..