Some addresses and ips are not reachable on my R7800 runing openwrt 18.06 [Solved]

I have a r7800 running 18.06 and I meet a wired problem. I work on it for a whole day and can not figure it out so come to ask for some suggestions from you guys. Thanks in head!

I have an ip 58.251.106.180, I can ping it with my mobile phone using 4G mobile network and can ping it from my computer from my office's network, and can ping it with my computer directly connected to a modern operated on Comcast network, but I can NOT ping it on my r7800, which means when I am using the wireless/wired connections and ping it from my phone or computer, it failed. It just stucks there without any output:

root@OpenWrt:~# ping 58.251.106.180
PING 58.251.106.180 (58.251.106.180): 56 data bytes

There are many addresses and IPs from China affected. I fastboot my r7800 but the problem stays. I am not a expert on networking, so not sure which direction should I go. Can some geniuses give me some suggestions about how to diagnose it. Really appreciate!

Some of my info:

Sorry for not including enough info:

  • What ISP is your R7800 on?
    Comcast
  • Are you in China?
    No, I am in United states
  • Is 58.251.106.180 assigned to the R7800?
    No, this address is a example that I can not ping or connect.
  • Otherwise, do you have normal Internet connectivity to other IP addresses?
    Yes, I have normal internet connectivity for addresses in US but don't have for many address in China.

Thanks for your remind!

@crotoc, welcome to the community!

  • If this IP should be ping-able now, it isn't.

You never provide enough information.

  • What ISP is your R7800 on?
  • Are you in China?
  • Is 58.251.106.180 assigned to the R7800?
  • Otherwise, do you have normal Internet connectivity to other IP addresses?

I can ping it from my router:

root@xeli:~# ping 58.251.106.180
PING 58.251.106.180 (58.251.106.180): 56 data bytes
64 bytes from 58.251.106.180: seq=0 ttl=47 time=351.920 ms
64 bytes from 58.251.106.180: seq=2 ttl=47 time=353.715 ms
64 bytes from 58.251.106.180: seq=3 ttl=47 time=354.125 ms
^C
--- 58.251.106.180 ping statistics ---
4 packets transmitted, 3 packets received, 25% packet loss
round-trip min/avg/max = 351.920/353.253/354.125 ms

Can you ping anything else, like 8.8.8.8 or 1.1.1.1 ?
If yes, then that host or your provider, or something in the middle might be blocking your requests.

A traceroute should indicate where are those pings being blocked.

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Yes I can ping 8.8.8.8 and 1.1.1.1 and also some Chinese address. But only many of them I can not ping.
It's strange that if I connect my computer directly to the comcast model, it works. Only when I add my router in the middle, It fails.

I tried traceroute and It seems that the packet goes to several steps and then stars appear.
I am doubting that my router's MAC is blocked by great firewall of China. Do you think it's possible? Does ping message enclose the message my routers mac?

Here is some backgrounds, I sometimes need to visit some Chinese website which only allow IPs from China, so I use some kind of vpn service on my router. For you information, the websites are all legal and doesn't have any kind of illegal content. But since yesterday, any vpn related to china IPs can't work through the network from the router but can be used on my phone by 4g mobile network. And as we know the existence of the great *** firewall, I am thinking of the possibility of problems of my router. Do you have suggestions to test this hypothesis?

Sorry for this:

  • What ISP is your R7800 on?
    Comcast

  • Are you in China?
    No, I am in United states

  • Is 58.251.106.180 assigned to the R7800?
    No, this address is a example that I can not ping or connect.

  • Otherwise, do you have normal Internet connectivity to other IP addresses?
    Yes, I have normal internet connectivity for addresses in US but don't have for many address in China.

Thanks for your remind!

I doubt MAC since that's impossible... but perhaps you mean IP address???

There's your issue. You're not in China!!!

YEP, it's starting to sound like your Comcast connection may be blocked by the great firewall.

  • So you are able to ping from the Comcast connection?
  • Did you set up a VPN on your router?
  • What kind of VPN technology?
  • Is it still enabled during your test?
  • Do you test ping from a Windows or Linux box?
  • Are you running ping on the OpenWrt, or from a client connected to it?
  • I'm really starting to think your IP has been flagged and blocked by the Great Firewall; or
  • Perhaps they blocked access to the VPN endpoint address

May still be illegal in China to do this...glad you're not there.

I am not sure. If it's ip's problem, why I am still able to ping when removing the router and directly connecting to Comcast.

Yes I am able to ping form the Comcast connection when I remove the router. So I think it may not be the problem of IP.

No I just used the VPN app from my android phone or android TV.

Not sure, it's some kind of VPN that will route the packets from specified apps with destination to China to their server located in china.

  • Is it still enabled during your test?

No

  • Do you test ping from a Windows or Linux box?
    From Windows subsystem linux (WSL) and termux on my android phone

  • Are you running ping on the OpenWrt, or from a client connected to it?
    I pinged from clients (phone/computer) and also from OpenWrt itself by login by SSH.

That may be the possible reason. Another symptom is that besides VPN, I have a VPS located in china and I can neither ping it nor connect to it when with router in the middle. But I am able to connect and ping it using Comcast directly when I remove the router from my connection. I will try to use a new router tonight to see what will happen.

So, it looks like packets are leaving your network, then being blocked outside. It would be interesting to see the complete output from a traceroute, both from your network and your phone.

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Because of your hints and others discussion, i tried to connect without router and figured that the ip address on the computer was different from the one on my router. So I guess ip may be flaged. Recently a lot of ss and ssr and v2ray airports are detected and flagged, I highly doute my ip is flaged because I have used a v2ray sevice. To test this, I needed to change the ip of my router. I did some research and figured that ip was related to mac in comcast. So I had to modify my router's mac. I figured there was a mac override option on wan's configuration page. I modified it and a new problem appeared as that my router could not get a ip even i rebooted both modem and router. Finally I used the diagnosis function on comcast website and restarted the modem remotely. Then the maricle happened, I could ping successfully. Thank you, guys. In summary, they flag my ip but not the mac.
Traceroute is a very great way to probe what's going on.

Appreciate all your guys' time and I am so happy i can visit the websites again! Hooray!

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grafik

Sure thanks!

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