Router not routing to USB 3G modem.

[Pila]

Asuswrt-Merlin RT-AC56U 380.58_0

USB 3G modem Huawei is connected to USB port as the only WAN connection. All seems to be configured well. When I did a test run with different mobile line, I had no problem. Now, I am on site 8 hours away, and I must install this, and something is wrong with routing.

Modem connects. It signals that with a light. Router receives WAN address correctly. I recieve DNS addresses from my provider correctly. My script updates DDNS correctly (verified). VPN server is up and I can connect to OpenVPN server on a router from another device using another data line. Ergo, the Internet is perfectly accessible to the router.

But, when I connect to the router with any device, e.g. computer, I can not conncet to the Internet from that device. I repeat: same setup with a differnet line (from my mobile phone) worked perfectly. Now in the modem is dedicated Data line. But, line from the phone is different (voice + data) and was double NAT-ed by my operator (WAN address is 10....) and this dedicated data line provides actual external WAN IP address, so - no double NAT now.

Tried rebooting a router with USB modem plugged and hot swapping modem out and back in. Same thing.

Seems to me the problem is caused by a routing table.

My current IP WAN is: 37.244.181.203

System Log - Routing Table - IPv4 Routing table seems to me off:

IPv4 Routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
10.64.64.64 * 255.255.255.255 UH 0 0 0 WAN
10.16.0.0 * 255.255.255.0 U 0 0 0 tun22
192.168.1.0 * 255.255.255.0 U 0 0 0 LAN
default 10.64.64.64 0.0.0.0 UG 0 0 0 WAN

which relates to the log:

Apr 22 12:47:00 kernel: option: v0.7.2:USB Driver for GSM modems
Apr 22 12:47:04 WAN Connection: Ethernet link up.
Apr 22 12:47:04 rc_service: wanduck 392:notify_rc restart_wan_if 0
Apr 22 12:47:05 dnsmasq[405]: read /etc/hosts - 5 addresses
Apr 22 12:47:19 WAN Connection: Fail to connect with some issues.
Apr 22 12:47:24 pppd[6617]: pppd 2.4.7 started by pila, uid 0
Apr 22 12:47:33 pppd[6617]: Serial connection established.
Apr 22 12:47:33 pppd[6617]: Using interface ppp0
Apr 22 12:47:33 pppd[6617]: Connect: ppp0 <--> /dev/ttyUSB0
Apr 22 12:47:36 pppd[6617]: Could not determine remote IP address: defaulting to 10.64.64.64
Apr 22 12:47:36 pppd[6617]: local  IP address 37.244.181.203
Apr 22 12:47:36 pppd[6617]: remote IP address 10.64.64.64
Apr 22 12:47:36 pppd[6617]: primary   DNS address 212.91.97.4
Apr 22 12:47:36 pppd[6617]: secondary DNS address 212.91.97.3
Apr 22 12:47:36 rc_service: ip-up 6700:notify_rc start_firewall
Apr 22 12:47:36 dnsmasq[405]: read /etc/hosts - 5 addresses
Apr 22 12:47:36 dnsmasq[405]: using nameserver 212.91.97.4#53
Apr 22 12:47:36 dnsmasq[405]: using nameserver 212.91.97.3#53
Apr 22 12:47:38 wan: finish adding multi routes
Apr 22 12:47:40 WAN Connection: WAN was restored.

Help is critically appreciated as I must fix this somehow VERY quicly because I am here only for a day or two. 8 hours away.

 

[Pila]

I think it is better to provide a more solid explanation, as it is apparantly yet another bug. OK, the above symptoms, router Asuswrt-Merlin RT-AC56U_380.58_0

1. When I was changing IP address of the router, LAN -> LAN IP -> IP Address, from 192.168.1.1 to 192.168.2.1 and vice versa, router said it will adjust the pool, but also filled LAN -> DHCP Server -> Default Gateway with the corresponding address. After a change of IP address, this gateway address remained wrong. At first, I did not noticed that but after a check, I found it and changed gateway to the right address. So, router was showing good gateway, but did not obey it! Hence, problem was as desribed above in the original post. Until I did a reboot, when it started working normally.

2. When I later needed to change IP address again, router hanged up after I pressed apply. Hard reboot, all is well, it remembered my new gateway entry and worked fine. Should I mention here that router must never hang when I change a setting?

3. The next day, I did nothing but use the router. No changes were made. At once, for no apparent reason, again the problem from my initial post. Whichever url I selected from my bookmarks in Firefox, I always got redirected to my router Login page. Again reboot, and all is fine.

As this router was previously used by me for several months to verify it works, I know how (un)stable it is: apart from USB dissapearing, it had many annoyance bugs, but worked well. But I never did change its IP or gateway addresses. This was practically the only change I applied at the new site. Apart from USB modem (instead of LAN modem) and DDNS script which I tested previously on another router for couple of days.

Question: do I need this gateway filled or can I leave it empty? On my another routers (connected to LAN modem behind double NAT) gateway field is empty.