All Questions
87
questions
0
votes
2
answers
111
views
Portforwarding Port 22 ( for ssh ) over JioFiber Router not working ( port 22 is closed )
I am using a JioFiber Router ( Firmware version : SRCMTF1_JCOW414_R2.52.1 ) . The host that I want to expose to the internet has Ubuntu Server 24.04.
Private IPs :
Router ...
0
votes
0
answers
30
views
Openvpn service running, not connecting to tunnel after changing iptables
I'm trying to make a kill switch for my pi to only allow traffic through the VPN. I made the changes below to iptables and disabled IPv6 in sysctl.conf. This is not my area of expertise so I'm hoping ...
- 1
1
vote
0
answers
41
views
Unable connect via port knocking
I am trying to set up port knocking on my server to enhance security. I've configured my firewall rules to use port knocking, where I have to connect to specific ports in a specific sequence before ...
- 11
4
votes
1
answer
955
views
I can't connect to Ubuntu server from local network, but can from outside
This is a weird one that has been driving me crazy for a while. I just can't work it out.
I'm running Ubuntu 22.04 (with all latest patches) on a Dell PowerEdge-r710 server. It's hosting a variety of ...
- 143
0
votes
0
answers
701
views
Connection via SSH works once or twice then never again for that client
I have recently set up a Ubuntu Server minimized. I initially used the server through an SSH with client1 but after one use I kept getting Connection Timed Out when attempting to ssh from client1. I ...
0
votes
1
answer
879
views
How to forward all or part of openvpn server traffic to another server through SSH tunnel?
I need to route all OpenVPN client traffic from Server A to Server B via SSH tunnel.
Client Server A Server B
------------------- ------...
-1
votes
1
answer
225
views
Connection closed by port 80 ubuntu
i have executed this code to copy a folder by my desk to my ubuntu instance
francesco@AirdiFrancesco ~ % scp /Users/francesco/Desktop/chimica [email protected]:/home/ubuntu
only that after this ...
- 1
0
votes
0
answers
288
views
Port forwarding in Ubuntu 20.04 causes pings to fail
I'm trying to forward ssh port to connect my servers together. Something like this:
Local Machine === (ssh) ===> Server A === (ssh) ===> Server B
My Servers aren't in a same location. They're ...
0
votes
0
answers
928
views
Opening Ports in Ubuntu 22.04
I understand that this may seem simple enough and there are many tutorials out there, but I've tried almost everything. My goal is to open any port on my Ubuntu desktop (starting with 22 for ssh) and ...
- 83
0
votes
0
answers
62
views
Can't access Ubuntu Server with SSH after doing something with iptables
I'm trying to run a MC-Server on an Ubuntu Sever (Oracle Cloud). I already port forwarded 25565 and 22 but still couldn't access the server. I found these commands on another tutorial, but when I ...
- 1
0
votes
0
answers
130
views
How do I get ssh to start working?
I turn an unused laptop into an Ubuntu server and everything was working great. I connected to it through ssh on my Windows 10 computer and was able to set up and access Nextcloud to upload all my ...
- 1
0
votes
1
answer
34
views
Sending packets on a dead port then stopping when accepting
I have programmed iptables to protect my Ubuntu installation. I have SSH but I have put it on another port than 22 for brute-force attacks.
However this morning, a single ip tried to connect every 30s-...
- 103
0
votes
1
answer
2k
views
Can not connect Ubuntu Server ssh from outside
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 ...
- 101
1
vote
1
answer
3k
views
Yet another SSH connection timeout [closed]
This one is puzzling me to no end. By using PuTTY (latest version) I was able to connect from Windows 10 to Ubuntu 18.04 via SSH (local network), and I've been doing it for over a year until it ...
- 21
0
votes
1
answer
2k
views
iptables - rule to block all other incoming traffic except ssh
I currently have the following rules to allow connections to my SSH server on port 2233:
iptables -A INPUT -p tcp --dport 2233 -m conntrack --ctstate NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -p ...
- 15
0
votes
2
answers
1k
views
Iptables that only allow incoming traffic to OpenSSH and block all other traffic
I need to configure a firewall using iptables that only allows incoming traffic to the openssh services and block all other traffic. I know how to block all incoming traffic but don't know how to only ...
- 15
0
votes
0
answers
216
views
Ubuntu SSH forwarding access not working from to server 3 from server 1 (server 1--> server 2 --> server 3)
i have a requirement to have the SSH connectivity of the remote server in the azure network to our on prem network. Since the direct connectivity between both the networks are not available, i am ...
0
votes
1
answer
619
views
IPTABLES/UFW: Deny ssh (on alternate port) requests from WAN, and allow ssh (on alternate port) from LAN. HOW TO?
I am running Ubuntu server version 20.04. I have configured my ssh server to listen on an alternate port (port 40001) in my sshd_config file. I want to allow incoming traffic from anywhere on my local ...
- 113
0
votes
4
answers
2k
views
I have a problem with SSH (or any port) I can't fix
I own a refurbished HP Proliant DL380 G7, for a small project I've been working on (It’s the first time using a server and setting it up). But after I set up Ubuntu 20.04 on it, the first thing I did ...
1
vote
1
answer
1k
views
can't ping outside, but curl wget works
I'm setting up a new server and this is driving me nuts.
I use a static IP, and have set it up correctly.
I can curl www.google.com, wget driver files, apt install, use teamviewer.
But I can't ...
- 13
1
vote
1
answer
1k
views
Why is iptables -F kicking me out of my ssh session?
I wanted to add some rules to iptables from this question and answers to route traffic from torrent programm Transmission through a vpn (surfshark in my case).
At least two of the answers use iptables ...
- 2,059
0
votes
0
answers
460
views
Is it safe to allow all port for local IPs in UFW?
Is it safe to allow all port for local IPs in UFW? I have a port forwarding set up on my router at a custom port for SSH reverse tunnelling to my SBC and it has 2FA on it. Thanks in advance!!
- 1
0
votes
2
answers
261
views
Locked SSH to a single IP and then lost that IP so I'm now locked out of the server
I thought locked SSH access to my IP would be a good thing but now I'm completely locked out and nothing I do in rescue mode seems to work.
I've tried changing/removing/uninstalling iptables but ...
0
votes
1
answer
2k
views
Ubuntu 20.04 - Port forwarding with iptables causing "temporary failure in name resolution" when using sudo
I'm working on a project where my Ubuntu machine port forwards external connections to a second computer on LAN running a game server. I found a few tutorials online on how to do this and ended up ...
0
votes
0
answers
73
views
Acces my ssh server from one of my internal LAN
I have attached a picture with my logical scheme of my network to understand better what I'm trying to say.
I have 2 routers, one it's from my ISP, let's say R1, and the second one it's a laptop with ...
- 1
0
votes
0
answers
279
views
SSH into Virtual Machine from outside of NAT router
I have a virtual machine on my host which I am trying to SSH from outside a NAT router. Both the host and the virtual machine are using the wifi interface and so have the same IP assigned by the home ...
1
vote
1
answer
5k
views
No SSH access after accidentally denied ssh in ufw/iptables on Snappy Ubuntu Core
I´m running Snappy Ubuntu Core 18.04 on Intel Nuc, located on other location then where I live permanently.
Now I have accidentally denied SSH in iptables with use of ufw and SSH connection is not ...
- 113
1
vote
2
answers
899
views
Random SSH IP from China
My nas server running ubuntu-server 19 has the 22 port open for remote access and I was just casually looking at netstat when I noticed a strange IP. Turns out it's from china and when I looked it up, ...
- 13
0
votes
0
answers
500
views
ufw prevents ssh into machine if it's connected to wireguard (Nordvpn)
I have several Ubuntu machines at home, some of them have ufw enabled and some not, I can ssh between them ok.
The problem comes when I connect a machine to wireguard vpn(Nordvpn service), from that ...
- 85
1
vote
1
answer
1k
views
Map a range of ports to another range of ports (equal lengths of ranges)
In this answer, How can I open a range of ports in ubuntu using (g)ufw, a simple command for opening a range of ports is given.
For example, using this command I can open the ports 1000-1999 very ...
- 227
0
votes
1
answer
507
views
SSH connection time out?
I'm using Ubuntu 16.04 and I'm trying to access via ssh from any computer. I've already altered the iptable configurations to accept all traffic from any IP, but I still got "the connection timed out" ...
0
votes
0
answers
3k
views
How to open port 22 with iptables
I am not able to ssh into an ec2-instance. when I run nmap -Pn 10.xxx.xxx.xx I see that instance doesn't have port 22 open
I have a security group added to this instance that has a ssh rule added. I ...
- 101
1
vote
1
answer
513
views
How to share hotspot through SSH tunnel?
I'm connected to a LAN, and want to provide a hotspot for a mobile phone.
Further, all the phones content should be served through a ssh socks5 tunnel, which is running with:
sshpass -p <pass> ...
- 1,420
0
votes
2
answers
2k
views
IPTables Configuration Causing Timeout
After adding the drop all rule to IPtables, my SSH terminal takes forever to load, often responding with error sudo: unable to resolve host foo.bar.domain: Connection timed out, but then immediately ...
- 113
2
votes
1
answer
176
views
sshguard - must a user declare behavior rules?
From this answer I understand that sshguard does include a default behavior that should suit most users, at least those with minimal webserver environments, yet it wasn't clear to me from the ...
2
votes
0
answers
166
views
Forward all traffic through one machine but still allow SSH connection
I currently have multiple machines M0,...,Mn connected by a switch. Additionally one designated management machine M0 has an additional NIC which is connected to the outside network (and internet). It ...
- 121
0
votes
0
answers
74
views
Ubuntu VM keeps rejecting incoming connections
Brand new Ubuntu 16.04 Server installed with just Postgres and OpenSSH servers in addition to the standard packages. After machine boots up, I can ssh and DB connect to the box. A few minutes later, I ...
- 1
1
vote
1
answer
919
views
UFW suddenly blocking SSH although allowed
I suddenly have problems with SSH and UFW. I have allowed the connection, but it only works if I disable UFW. I have run out of ideas.
The output of ufw status is
Status: active
To ...
- 121
0
votes
0
answers
830
views
How to Access Ubuntu Server behind double NAT?
My ISP has provided me a private IP and the cable is plugged to wifi router.
I am running Ubuntu 16.04 server on my machine. I have read guides that say basically i can connect to my server even when ...
- 11
0
votes
1
answer
74
views
How do I block large ranges of IPs independent of server-specific options?
I got tired of being trolled by international users constantly probing around the edges of my SSH server, and while DenyHosts was a good starting point for managing SSH access, I decided I wanted ...
- 409
2
votes
1
answer
21k
views
SSH port 22: Connection refused
I'm using Lubuntu 17.04, I tried to copy a file using "scp" remotely through ssh but logged in the host computer, not local. Ater that when I try to login via ssh I get this error "...
5
votes
3
answers
30k
views
How to debug ssh incoming connections?
I'm having troubles ssh-ing to a server (ubuntu 16.04) I have root access to from my machine (macOS 10.12). The situation is weird: I checked that sshd is running on the server and that the port 22 is ...
- 173
0
votes
1
answer
98
views
Remote backup servers are denied connection?
I got an reoccuring issue with a few remote backup machines I got. I have a few cron jobs that runs a backup schedule but after a while they stop working. I quickly found that even simple pings wont ...
- 630
9
votes
1
answer
20k
views
Step by Step enable remote login to home ubuntu machine?
To clarify, this is ask:
I have a home computer running ubuntu. I want to be able to ssh into it from a remote location such as a cafe where I will bring a laptop.
My attempts thus far have been ...
- 143
1
vote
1
answer
4k
views
Ubuntu 16.04.2 LTS won't allow incoming ssh connections
Going on a few days now I cant SSH into my Ubuntu 16.04.2 LTS server. Everything else is working fine as far as I can tell (it serves a few websites and they're all online no prob). When I try to SSH ...
- 21
4
votes
1
answer
17k
views
How to allow only ssh and internet access with iptables?
I want to allow only internet access (it is useful for update) and ssh on my server. I found this set of rules:
sudo iptables -P INPUT DROP
sudo iptables -P OUTPUT DROP
sudo iptables -A INPUT -...
- 1,997
-1
votes
3
answers
10k
views
How to fix iptables if i have blocked all incoming and outgoing connections?
I am using Ubuntu Server (Amazon EC2) and connected with ssh using putty
I was setting up iptables to block all incoming and outgoing connection except my ip address, I tried these commands from putty:...
- 139
4
votes
1
answer
1k
views
Can't connect to server via SSH outside Web Console
If I try to connect to my server via any console, etc.:
➤ ssh -vv xx.xx.xxx.xx:1337
OpenSSH_7.1p2, OpenSSL 1.0.1g 7 Apr 2014
debug1: Reading configuration data /etc/ssh_config
_ssh: Could not ...
- 227
1
vote
0
answers
241
views
HTTP/SSH request not passing through some iptables rules
I have an assignment to do using iptables to create a set of rules.
Using marionnet, we simulate the following network:
What we want here is to avoid "intrus" from being able to interact with the ...
1
vote
0
answers
782
views
Cannot even ping my WAN ip outside LAN!
I want to set up my computer as an SSH server on WAN (so I can access it from everywhere). I set up DMZ with my router and installed sshd, and I can connect and log in to it from within my LAN using ...
