My website - deepcoder.co.uk - is being blocked only for computers

[DeepCoder]

My website - deepcoder.co.uk - is being blocked only for computers ?

I open my website on my PC and it won't work. Then i tried another PC and still it won't work. But when i open it on a iphone without a sim card. It works.

It only happens on my router and i reset it and restarted it but still it won't work

Could someone help me ?

[XRaySpeX]

Do you have fixed or mobile home BB? 

I have no trouble accessing your website over EE fixed Home BB.

Are your PCs connected to the router by Ethernet or WiFi? Which router is it?

[DeepCoder]

Wifi & Ethernet 

My router is EE smart hub

[mikeliuk]

Hi @DeepCoder ,

On your PC, please try to access the server directly via the IP address 199.188.200.112

When debugging access to a website, there are two key phases to the debugging:

1. Name resolution; and
2. Routing

Below I show a check of the name lookup on a Linux server. You may use "nslookup" under Windows 10 to debug that step.

If you are using "ftp" as nmap suggests is a possibility, I would highly recommend that you do not. A search online should give ample reasons for why not.

[x@x ~]$ for i in 8.8.8.8 1.1.1.1; do dig @$i deepcoder.co.uk; done

; <<>> DiG 9.11.20-RedHat-9.11.20-5.el8 <<>> @8.8.8.8 deepcoder.co.uk
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 42435
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;deepcoder.co.uk. IN A

;; ANSWER SECTION:
deepcoder.co.uk. 1199 IN A 199.188.200.112

;; Query time: 69 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Sat Jul 03 11:27:46 BST 2021
;; MSG SIZE rcvd: 60

; <<>> DiG 9.11.20-RedHat-9.11.20-5.el8 <<>> @1.1.1.1 deepcoder.co.uk
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 3027
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;deepcoder.co.uk. IN A

;; ANSWER SECTION:
deepcoder.co.uk. 1143 IN A 199.188.200.112

;; Query time: 19 msec
;; SERVER: 1.1.1.1#53(1.1.1.1)
;; WHEN: Sat Jul 03 11:27:46 BST 2021
;; MSG SIZE rcvd: 60

[x@x ~]$ nmap 199.188.200.112
Starting Nmap 7.70 ( https://nmap.org ) at 2021-07-03 11:30 BST
Nmap scan report for server237-5.web-hosting.com (199.188.200.112)
Host is up (0.15s latency).
Not shown: 986 filtered ports
PORT STATE SERVICE
20/tcp closed ftp-data
21/tcp open ftp
25/tcp open smtp
26/tcp open rsftp
53/tcp open domain
80/tcp open http
110/tcp open pop3
113/tcp closed ident
143/tcp open imap
443/tcp open https
465/tcp open smtps
587/tcp open submission
993/tcp open imaps
995/tcp open pop3s

Nmap done: 1 IP address (1 host up) scanned in 15.06 seconds

[DeepCoder]

I can connect to it 

[mikeliuk]

Hi @DeepCoder ,

Therefore you have a name resolution issue.

I would recommend reverting to the DNS servers provided by your domain name provider in the first instance.

You have port 53 open which for another user I saw they had the server set as the authoritative DNS for its own name which is a bit of a chicken and egg issue.

[XRaySpeX]

You do have a DNS issue but at home not at your domain host.

To get round this issue switch the DNS in the router away from EE's ones to Manual with 1 of these public DNS pairs:

OpenDNS   :	208.67.222.222 & 208.67.220.220
Google DNS:	8.8.8.8 & 8.8.4.4 
Cloudflare DNS	1.1.1.1 & 1.0.0.1  

[DeepCoder]

I changed my dns to 1.1.1.1 and 1.0.0.1 and still it dosen't work !

I tried flushing my dns and restarting my pc but it won't work

[mikeliuk]

Hi @DeepCoder ,

Assuming you use Windows 10, please see this article for how to use nslookup directly against a particular DNS server: https://social.technet.microsoft.com/wiki/contents/articles/29184.nslookup-for-beginners.aspx

I've just checked again below and both Google DNS and Cloudflare DNS resolve the domain name. I recommend to reproduce this known-good result before you proceed any further.

When you say you have changed your DNS, where did you do this? On the router, or on a client server?

[x@x ~]$ for i in 8.8.8.8 1.1.1.1; do nslookup deepcoder.co.uk $i; done; date
Server: 8.8.8.8
Address: 8.8.8.8#53

Non-authoritative answer:
Name: deepcoder.co.uk
Address: 199.188.200.112

Server: 1.1.1.1
Address: 1.1.1.1#53

Non-authoritative answer:
Name: deepcoder.co.uk
Address: 199.188.200.112

Sun 4 Jul 14:56:31 BST 2021

On the positive side, the authoritative name servers seem to be your domain name provider's servers so that's a good thing.

[x@x ~]$ dig @199.188.200.112 deepcoder.co.uk

; <<>> DiG 9.11.20-RedHat-9.11.20-5.el8 <<>> @199.188.200.112 deepcoder.co.uk
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 1695
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;deepcoder.co.uk. IN A

;; ANSWER SECTION:
deepcoder.co.uk. 1200 IN A 199.188.200.112

;; AUTHORITY SECTION:
deepcoder.co.uk. 1800000 IN NS dns2.namecheaphosting.com.
deepcoder.co.uk. 1800000 IN NS dns1.namecheaphosting.com.

;; Query time: 194 msec
;; SERVER: 199.188.200.112#53(199.188.200.112)
;; WHEN: Sun Jul 04 14:58:09 BST 2021
;; MSG SIZE rcvd: 118

I use Quad9 DNS on my router and that website looks fine to me on both port 80 and 443. https://www.quad9.net/

I assume you don't have anything like an equivalent to /etc/hosts which resolves your name locally to an old IP address that is no longer valid for that server. A straight forward "nslookup deepcoder.co.uk" should tell you what IP address your PC believes the name resolves to.

[DeepCoder]

nslookup : 

https://prnt.sc/18irik1

Web :

https://prnt.sc/18irz0p