Can't access linux server in local network

Question

Problem: Unable to access Linux Mint 20.1 PC from Windows PC after changing new router (TP-Link AX11000)

Router: TP-Link AX11000

Machine 1: Windows 10 PC

Machine 2: Linux Mint 20.1 PC

I was able to winscp / nomachine / ssh from my Windows 10 PC to my Linux Mint 20.1 PC until I changed to new router, and new IP was assign to every device. I am not sure if the problem is due to:

1. ax11000 blocking the connection
2. outdated PC configuration due to new IP
3. Linux Mint 20.1's firewall (I disabled firewall with sudo ufw disable and try connecting with the methods mentioned below, and it's don't work. So I don't think firewall is the problem)
4. something else

WinSCP error:

Network error: Connection to "192.168.0.231" timed out

NoMachine error:

A connection timeout has occurred while trying to connect to '192.168.0.231' on port '4000'. The issue could either be caused by a networking problem, by a firewall or NAT blocking incoming traffic or by a wrong server address. Please verify your configuration and try again.

• UPnP (Universal Plug and Play) is enabled and port 4000 created by NoMachine is present.

SSH error:

# standard ssh to my linux mint don't work as expected
$ ssh -v [email protected]
OpenSSH_8.2p1 Ubuntu-4ubuntu0.1, OpenSSL 1.1.1f  31 Mar 2020
debug1: Reading configuration data /home/USER/.ssh/config
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: include /etc/ssh/ssh_config.d/*.conf matched no files
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug1: Connecting to 192.168.0.231 [192.168.0.231] port 22.
debug1: connect to address 192.168.0.231 port 22: No route to host
ssh: connect to host 192.168.0.231 port 22: No route to host

# ping the IP address to ensure linux mint pc is up (it's because I am looking at the mint pc), from my Windows to my Linux
ping 192.168.0.231
PING 192.168.0.231 (192.168.0.231) 56(84) bytes of data.
From 192.168.0.194 icmp_seq=7 Destination Host Unreachable
From 192.168.0.194 icmp_seq=10 Destination Host Unreachable
From 192.168.0.194 icmp_seq=13 Destination Host Unreachable
From 192.168.0.194 icmp_seq=16 Destination Host Unreachable
From 192.168.0.194 icmp_seq=19 Destination Host Unreachable
From 192.168.0.194 icmp_seq=22 Destination Host Unreachable
From 192.168.0.194 icmp_seq=25 Destination Host Unreachable
^C
--- 192.168.0.231 ping statistics ---
25 packets transmitted, 0 received, +7 errors, 100% packet loss, time 24778ms

IP info:

$ sudo netstat -anutp | grep :22
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      64417/sshd: /usr/sb 
tcp6       0      0 :::22                   :::*                    LISTEN      64417/sshd: /usr/sb

$ ip addr
...
    inet 192.168.0.231/24 brd 192.168.0.255 scope global dynamic noprefixroute wlp59s0
...

$ hostname -I
192.168.0.231

$ ip r
192.168.0.0/24 dev wlp59s0 proto kernel scope link src 192.168.0.231 metric 600

How I setup my router: https://www.tp-link.com/us/user-guides/archer-ax11000_v1/chapter-4-set-up-internet-connection#ug-sub-title-1

AX11000 System Diagnostics Output:

# Windows 10 PC ping
PING 192.168.0.194 (192.168.0.194): 64 data bytes
Reply from 192.168.0.194: bytes=64 ttl=128 seq=1 time=1.632 ms
Reply from 192.168.0.194: bytes=64 ttl=128 seq=2 time=1.620 ms
Reply from 192.168.0.194: bytes=64 ttl=128 seq=3 time=1.327 ms
Reply from 192.168.0.194: bytes=64 ttl=128 seq=4 time=1.722 ms
--- Ping Statistic "192.168.0.194" ---
Packets: Sent=4, Received=4, Lost=0 (0.00% loss)
Round-trip min/avg/max = 1.327/1.575/1.722 ms
ping is stopped. 

# Windows 10 PC traceroute
traceroute to 192.168.0.194, 5 hops max, 38 byte packets
1 * * *
2 * * *
3 * * *
4 * * *
5 * * *
Trace Complete.
traceroute is stopped. 

# Linux Mint 20.1 PC ping
PING 192.168.0.231 (192.168.0.231): 64 data bytes
Reply from 192.168.0.231: bytes=64 ttl=64 seq=1 time=7.350 ms
Reply from 192.168.0.231: bytes=64 ttl=64 seq=2 time=1.145 ms
Reply from 192.168.0.231: bytes=64 ttl=64 seq=3 time=1.307 ms
Reply from 192.168.0.231: bytes=64 ttl=64 seq=4 time=2.178 ms
--- Ping Statistic "192.168.0.231" ---
Packets: Sent=4, Received=4, Lost=0 (0.00% loss)
Round-trip min/avg/max = 1.145/2.995/7.350 ms
ping is stopped. 

# Linux Mint 20.1 PC traceroute
traceroute to 192.168.0.231, 5 hops max, 38 byte packets
1 192.168.0.231 (192.168.0.231) 35.597 ms 35.319 ms 1.242 ms
Trace Complete.
traceroute is stopped. 

Any response / pointer / help will be greatly appreciated!

Answer 1

This is embarrassing, but after restarting my router again makes the problem disappear, I swear that I did that and confirm it don't work before I post the question here.

I reach out to TP-Link support to go through the problems with them. Here are some settings to look out for if you are using TP-Link AX11000 and face the same problem

Advanced > Wireless > Wireless Settings

• Security: WPA/WPA2-Personal
• Version: WPA-PSK/WPA2-PSK
• Encryption: AES

Advanced > Wireless > Additional Settings

• Make sure AP Isolation is disabled

Advanced > System > Firmware Upgrade

• Make sure Firmware is up to date

After ensuring these settings are right, shutdown the router, wait for 5 mins, before starting it again. It should work now, fingers cross.

Also, special thanks to user @Zina for the help.