We have ubuntu server installed on our desktop machine. It is connected modem with ethernet port. We can access it with ssh via inside of our network. But can not from outside.
Here is what we've done so far:
We have static ip
My professor made this i dont know what it is
Our ubuntu server machine always picks 192.168.1.200
We have port forwarding
when I run ssh maviarge#213.XXXXXXX from our LAN which holds ubuntu server machine
maviarge#213.XXXXXXX's password:
Welcome to Ubuntu 20.04.4 LTS (GNU/Linux 5.4.0-104-generic x86_64)
* Documentation: https://help.ubuntu.com
* Management: https://landscape.canonical.com
* Support: https://ubuntu.com/advantage
System information as of Thu 10 Mar 2022 08:45:36 AM UTC
System load: 0.07 Processes: 166
Usage of /: 2.0% of 438.13GB Users logged in: 1
Memory usage: 2% IPv4 address for docker0: 172.17.0.1
Swap usage: 0% IPv4 address for enp3s0: 192.168.1.200
Temperature: 50.0 C
* Super-optimized for small spaces - read how we shrank the memory
footprint of MicroK8s to make it the smallest full K8s around.
https://ubuntu.com/blog/microk8s-memory-optimisation
0 updates can be applied immediately.
But when I run ssh -v maviarge#213.XXXXXXX from outside of our wifi.
OpenSSH_for_Windows_8.1p1, LibreSSL 3.0.2
debug1: Reading configuration data C:\\Users\\MaviArge/.ssh/config
debug1: Connecting to 213.XXXXXXX [213.XXXXXXX] port 22.
debug1: connect to address 213.XXXXXXX port 22: Connection timed out
ssh: connect to host 213.XXXXXXX port 22: Connection timed out
When I run ping 213.XXXXXXX from outside
Pinging 213.XXXXXXX with 32 bytes of data:
Reply from 213.XXXXXXX: bytes=32 time=67ms TTL=46
Reply from 213.XXXXXXX: bytes=32 time=97ms TTL=46
Reply from 213.XXXXXXX: bytes=32 time=107ms TTL=46
Reply from 213.XXXXXXX: bytes=32 time=124ms TTL=46
Ping statistics for 213.XXXXXXX:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 67ms, Maximum = 124ms, Average = 98ms
Saw this command on internet sudo lsof -i:22 and the output:
sudo lsof -i:22
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
sshd 3290 root 4u IPv4 38814 0t0 TCP maviarge:ssh->host-213.XXXXXXX.reverse.superonline.net:58124 (ESTABLISHED)
sshd 3375 maviarge 4u IPv4 38814 0t0 TCP maviarge:ssh->host-213.XXXXXXX.reverse.superonline.net:58124 (ESTABLISHED)
sshd 4057 root 3u IPv4 71589 0t0 TCP *:ssh (LISTEN)
sshd 4057 root 4u IPv6 71591 0t0 TCP *:ssh (LISTEN)
sshd 5662 root 4u IPv4 74261 0t0 TCP maviarge:ssh->host-213.XXXXXXX.reverse.superonline.net:60472 (ESTABLISHED)
sshd 5746 maviarge 4u IPv4 74261 0t0 TCP maviarge:ssh->host-213.XXXXXXX.reverse.superonline.net:60472 (ESTABLISHED)
Also nmap scan:
Starting Nmap 7.92 ( https://nmap.org ) at 2022-03-10 05:17 EST
Nmap scan report for host-213.XXXXXXX.reverse.superonline.net (213.XXXXXXX)
Host is up (0.14s latency).
Not shown: 96 closed tcp ports (reset)
PORT STATE SERVICE
22/tcp filtered ssh
25/tcp filtered smtp
5060/tcp filtered sip
5432/tcp open postgresql
Nmap done: 1 IP address (1 host up) scanned in 2.08 seconds
What's wrong?
have you try this
sudo ufw allow from any to any port 22 proto tcp
or
sudo ufw allow ssh
Related
I want to access my NextJs dev server running on WSL2 on my local network.
I added port 3000 to firewall rules and tested with telnet and it was not immediately accessible.
After some research I found this document: https://learn.microsoft.com/en-us/windows/wsl/networking
So I ran on my WSL2 instance:
cat /etc/resolv.conf
# This file was automatically generated by WSL. To stop automatic generation of this file, add the following entry to /etc/wsl.conf:
# [network]
# generateResolvConf = false
nameserver 172.23.16.1
I confirmed the WSL2 IP address is correct by pinging from host machine:
ping 172.23.16.1
Pinging 172.23.16.1 with 32 bytes of data:
Reply from 172.23.16.1: bytes=32 time<1ms TTL=128
Reply from 172.23.16.1: bytes=32 time<1ms TTL=128
Reply from 172.23.16.1: bytes=32 time<1ms TTL=128
Reply from 172.23.16.1: bytes=32 time<1ms TTL=128
Then using that IP to run this command on the windows 11 host from an elevated prompt:
netsh interface portproxy add v4tov4 listenport=3000 listenaddress=0.0.0.0 connectport=3000 connectaddress=172.23.16.1
Now I am able to telnet into the windows host on 192.168.0.50:3000 (this is local IP of host) but there is no helo and if I try to access it via web browser I get ERR_EMPTY_RESPONSE
The proxy port appears to be there:
netsh interface portproxy show v4tov4
Listen on ipv4: Connect to ipv4:
Address Port Address Port
--------------- ---------- --------------- ----------
0.0.0.0 3000 172.23.16.1 3000
I tried adding a few more proxy ports
Listen on ipv4: Connect to ipv4:
Address Port Address Port
--------------- ---------- --------------- ----------
0.0.0.0 3000 172.23.16.1 3000
192.168.0.50 3000 172.23.16.1 3000
127.0.0.1 3000 172.23.16.1 3000
Still getting ERR_EMPTY_RESPONSE over the LAN. I can connect via telnet to the port so I'm guessing it's something to do with the WSL2 Ubunto 20.04 installation.
I am not sure why I cant access it. There is no firewall active in WSL2
ufw status
Status: inactive
If I try to access localhost:3000 on host machine it works. If I try to access http://192.169.0.50:3000/ on host machine I get the error so there has to be a binding missing somewhere but I don't know where.
How can I debug this?
The docs seem to be incorrect. ipconfig and the resolv.conf seem to show wrong IP address.
To get the correct IP address I needed to use: wsl hostname -I from powershell
I ran the raspbian image with the following command:
qemu-system-arm -kernel kernel-qemu-4.19.50-buster -cpu arm1176 -m 256 -M versatilepb -dtb versatile-pb.dtb -no-reboot -serial stdio -append "root=/dev/sda2 panic=1 rootfstype=ext4 rw" -drive "file=2020-02-13-raspbian-buster-lite.img,index=0,media=disk,format=raw" -net user,hostfwd=tcp::5022-:22 -net nic -net user,smb=/dev/shm/
Booting the image completed successfully.
Withing guest machine I get the following routing table:
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 10.0.2.2 0.0.0.0 UG 202 0 0 eth0
10.0.2.0 0.0.0.0 255.255.255.0 U 202 0 0 eth0
Now when pinging the gateway at 10.0.2.2 works fine, but when pinging the host machine or the host gateway at 10.0.0.138 I get:
pi#raspberrypi:~$ ping 10.0.0.138
PING 10.0.0.138 (10.0.0.138) 56(84) bytes of data.
64 bytes from 10.0.0.138: icmp_seq=1 ttl=255 time=1.19 ms
64 bytes from 10.0.0.138: icmp_seq=1 ttl=255 time=1.23 ms (DUP!)
I verified that 10.0.0.138 isn't defined as broadcast address, and there are no IP duplications. Any idea how to debug from here? Thanks
As Peter Maydell suggested, merging the two options into one "-net user,smb=/dev/shm/,hostfwd=tcp::5022-:22" solved the case.
This is because QEMU creates a new 'user' network backend for each use of '-net user' on the command line, so in the original commandline there were two backends, each of which was responding to ping packets.
I have a google compute running CentOS 7, and I wrote up a quick test to try and communicate with it over port 9000 (from my home PC) - but I'm unexpectedly getting network errors.
This happens both with my test script (which attempts to send a payload) and even with plink.exe (which I'm just using to check the port availability).
>plink.exe -v -raw -P 9000 <external_IP>
Connecting to <external_IP> port 9000
Failed to connect to <external_IP>: Network error: Connection refused
Network error: Connection refused
FATAL ERROR: Network error: Connection refused
I've added my external IP to googles firewall (https://console.cloud.google.com/networking/firewalls) and set to allow ingress traffic over port 9000 (it's the lowest priority, at 1000)
I also updated firewalld in CentOS to allow TCP traffic over the port:
Redirecting to /bin/systemctl start firewalld.service
[foo#bar ~]$ sudo firewall-cmd --zone=public --add-port=9000/tcp --permanent
success
[foo#bar ~]$ sudo firewall-cmd --reload
success
I've confirmed my listener is running on port 9000
[foo#bar ~]$ netstat -npae | grep 9000
(Not all processes could be identified, non-owned process info
will not be shown, you would have to be root to see it all.)
tcp 0 0 127.0.0.1:9000 0.0.0.0:* LISTEN 1000 18381 1201/python3
By default, CentOS 7 doesn't use iptables (just to be sure, I confirmed it wasn't running)
Am I missing something?
NOTE: Actual external IP replaced with <external_IP> placeholder
Update:
If I nmap my listener over port 9000 from the CentOS 7 compute instance over a local IP, like 127.0.0.1 I get some results. Interestingly, if I make the same nmap call over the servers external IP -- nadda. So this has to be a firewall, right?
external call
[foo#bar~]$ nmap <external_IP> -Pn
Starting Nmap 6.40 ( http://nmap.org ) at 2020-05-25 00:33 UTC
Nmap scan report for <external_IP>.bc.googleusercontent.com (<external_IP>)
Host is up (0.00043s latency).
Not shown: 998 filtered ports
PORT STATE SERVICE
22/tcp open ssh
3389/tcp closed ms-wbt-server
Nmap done: 1 IP address (1 host up) scanned in 4.87 seconds
Internal Call
[foo#bar~]$ nmap 127.0.0.1 -Pn
Starting Nmap 6.40 ( http://nmap.org ) at 2020-05-25 04:36 UTC
Nmap scan report for localhost (127.0.0.1)
Host is up (0.010s latency).
Not shown: 997 closed ports
PORT STATE SERVICE
22/tcp open ssh
25/tcp open smtp
9000/tcp open cslistener
Nmap done: 1 IP address (1 host up) scanned in 0.10 seconds
In this case software running on the backend VM must be listening any IP (0.0.0.0 or ::), your's is listening to "127.0.0.1:9000" and it should be "0.0.0.0:9000".
The way to fix that it's to change the service config to listen to 0.0.0.0 instead of 127.0.0.1 .
Cheers.
Scenario...
WiFi Network home = Can connect with my Digital Ocean servers fine via SSH;
WiFi Network work = Can't connect with my Digital Ocean servers via SSH;
WiFi Network work SSH debug:
OpenSSH_6.6.1, OpenSSL 1.0.1f 6 Jan 2014
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: ssh_connect: needpriv 0
debug1: Connecting to xxx.xxx.xxx.xxx [xxx.xxx.xxx.xxx] port 22.
debug1: connect to address xxx.xxx.xxx.xxx port 22: Connection timed out
ssh: connect to host xxx.xxx.xxx.xxx port 22: Connection timed out
Anyone?
Try to check with nc
nc -zvw4 your_host 22
If not open - probably 22 port not allowed in your network, you can ask your network administrator about it
on your server make forward from 443 to 22 via iptables, for example:
iptables -t nat -I PREROUTING -i eth0 -p tcp -m tcp --dport 443 -j REDIRECT --to-ports 22
I have a virtual machine located inside a private network.
So firstly, I should come in server.com and then come in my-machine.
I want to make ssh-tunnel from my laptop to my-machine.
ssh -v -A -nNT -L 40000:127.0.0.1:40000 login#server.com ssh -v -nNT -L 40000:127.0.0.1:40000 my-machine &
Now I want to test ssh-tunnel with netcat.
I run at my-machine:
nc -l 40000
At my laptop:
~ ❯❯❯ nc 127.0.0.1 40000
But it gives me:
debug1: Connection to port 40000 forwarding to 127.0.0.1 port 40000 requested.
debug1: channel 2: new [direct-tcpip]
channel 2: open failed: connect failed: Connection refused
debug1: channel 2: free: direct-tcpip: listening port 40000 for 127.0.0.1 port 40000, connect from 127.0.0.1 port 49692 to 127.0.0.1 port 40000, nchannels 3
Why this happen and how to fix it? I expected that anything I type in my laptop console will appear in my-machine console.
What last string means? Especially 127.0.0.1 port 49692 why this port is used? I never type it.
debug1: channel 2: free: direct-tcpip: listening port 40000 for 127.0.0.1 port 40000, connect from 127.0.0.1 port 49692 to 127.0.0.1 port 40000, nchannels 3
Every TCP connection is point to point needs two pairs of IP addresses and ports. Reading all the message (not just the part you showed):
connect from 127.0.0.1 port 49692
So indeed you are connecting to the port 40000, but you are connecting from port 49692 (randomly assigned for your netcat or some of the forwarded steps).
How to fix this problem?
This double-jump forwarding does not work, because you need the second established before the first one.
Also you are using -N switch for the first command, which is preventing running the second ssh command.
But I would give it a shot with ProxyCommand, which will make you connect to the destination with single command directly from your host:
ssh -v -nNT -L 40000:127.0.0.1:40000 \
-oProxyCommand="ssh -W %h:%p login#server.com" my-machine &