Need some knowledge about DNS, I am trying to see what I can do to prevent it happen again

Forums › LAN (ethernet/Wifi/routers/Bluetooth) › Need some knowledge about DNS, I am trying to see what I can do to prevent it happen again

iamsammajor

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#279939 18-Nov-2020 13:16

Dear All,

the long story started when I realised I cant access normal Chinese website that i usually go to, like Taobao, Alicloud, Baidu or JD... the list goes on.

initially I thought that was ISP problem, so I got my friend who is with the same ISP to do some test and he has not issue at all.

I move back to the Fritzbox thinking it was router, but had no luck.

Tried the VPN and all websites seems working once connected to VPN.

it got me thinking it might be something to do with my static IP.

rang 2degree to temporary lift my static IP and everything seems working fine.

so my question is

does the symptom indicate I was under any attack? as I do need Static IP so my parent could steam from my plex server.

im trying to see what I could do to prevent it from happening again, if it does indicate it was.

thanks advance and sorry im not really good at telling story.

Cheers,

Sam

Dynamic

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#2605967 18-Nov-2020 13:20

That does seem odd. Is it possible your IP was blocked by 'the great firewall of China'?

Just in case anyone was wondering, no I'm not being flippant or disrespectful.

“Don't believe anything you read on the net. Except this. Well, including this, I suppose.” Douglas Adams

iamsammajor

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#2605975 18-Nov-2020 13:35

Dynamic:

That does seem odd. Is it possible your IP was blocked by 'the great firewall of China'?

Just in case anyone was wondering, no I'm not being flippant or disrespectful.

I did wonder that was the case as well, but seems cant think of any reason, however apps seems working perfectly,

i would have thought if it was the great firewall, it would be all in or nothing.

XD dont worry, i found the wall is annoying too lol

timmmay

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#2605976 18-Nov-2020 13:36

This looks like blacklisting an IP possibly by a system in or controlled by China, unlikely to be anything to do with an attack.

yitz

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#2605977 18-Nov-2020 13:37

Do you get any error messages or do requests to those sites just time out?

Why do you think it is related to the DNS?

iamsammajor

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#2605978 18-Nov-2020 13:40

yitz:

Do you get any error messages or do requests to those sites just time out?

Why do you think it is related to the DNS?

Im not 100% sure it was DNS, that is the only think I can think of, because web browsing doesnt work, but the app does.

yitz

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#2605982 18-Nov-2020 13:47

iamsammajor: web browsing doesnt work, but the app does.

What does the web browser display? Can you provide a screenshot?

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iamsammajor

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#2605992 18-Nov-2020 14:02

yitz:

iamsammajor: web browsing doesnt work, but the app does.

What does the web browser display? Can you provide a screenshot?

i need to try get the static IP reinstate before I could replicate what shows in browser. what I can remember is that when try to Ping the URL didnt get any response.

yitz

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#2606106 18-Nov-2020 14:30

timmmay: This looks like blacklisting an IP possibly by a system in China, unlikely to be anything to do with an attack.

These sites will be hosted behind a globally distributed CDN so it sounds like the OP is being blocked by a WAF rule.

iamsammajor

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#2606159 18-Nov-2020 14:45

yitz:

timmmay: This looks like blacklisting an IP possibly by a system in China, unlikely to be anything to do with an attack.

These sites will be hosted behind a globally distributed CDN so it sounds like the OP is being blocked by a WAF rule.

is there anyway to find out reason being blocked, it is really annoying lol,

DjG

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#2606434 18-Nov-2020 17:24

do an mturoute https://www.elifulkerson.com/projects/mturoute.php

you will see that the mtu goes to a very small number once you hit the Chinese networks, if so they you have been blocked by the great firewall

iamsammajor

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#2606587 19-Nov-2020 07:42

got 2D to reinstate my static IP but they couldnt give me the same old one,

I dont have any issue with the new one (touch wood)

so far the IP-blocking theory makes most sense, thank you all for your generous help

thanks,

Sam

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1101

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#2606618 19-Nov-2020 09:08

Sometimes the static IP given by the ISP is 'dirty' : on some blacklists because of previous holder of that IP

I had 2 'dirty' static IP's in a row when a client changed ISP's
I now allways do some checking to see if ~new~ static IPs are on any blacklists .

Yoban

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#2606624 19-Nov-2020 09:18

Could also setup a Dynamic DNS (say duckdns.org) as a backup or a test mechanism.

Could it also be possible to have VPN and get them to get access to Plex through VPN tunnel.

iamsammajor

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#2606626 19-Nov-2020 09:22

Yoban:

Could also setup a Dynamic DNS (say duckdns.org) as a backup or a test mechanism.

Could it also be possible to have VPN and get them to get access to Plex through VPN tunnel.

im working on setting up VPN for Plex, thats my blackup plan just in case.