USB Ports not working in linux

we have multiple systems which are installed on the same way. Now we have a bad situation, ANY USB-Port will not work on two PCs while using ubuntu 18.04.02 server version.

The usb ports working fine on ubunut 18.04.02 (desktop) and windows, so the hardware cant be malfunction.

I tried some stuff: I already did a bios reset. Reinstalled Ubuntu 18.04.02 server (which also not work, but if i install it on a other pc (same hardware/modell) it works fine). I tested different other keyboards/devices. I tested all usb-ports In dmesg/sys logs i cant see any new line about usb. In commands like lsusb there are NO usb devices.

Have you a idea for that ? I dont understand it, because we have multiple Devices (same model/hardware) which are installed on the same way but on two of 15 devices its not working…

How to perform a security test/review/penetration testing of Ethernet ports?

So recently I have been engaged by a client who wants it’s Ethernet ports checked that whether port security is functioning effectively.

  1. What can be the approach or steps to do check Ethernet port security?

  2. What tools can be used to do the same?

  3. In the scenario that if I am third party who enters in an
    organization with his/her laptop and sees that there are Ethernet
    ports around. Then I decide to plug in a wire and try to get into the network. What can I do to achieve that?

Serial ports Issue ( Not USB, the ttyS ones ) Ubuntu 16.04

I have a machine running ubuntu 16.04, before ubuntu the machine had CentOS 6.5 installed, the pc has 3 serial ports ( /dev/ttyS[0-2] ) before the OS change these ports were working fine but now every time a device tries to open them it doesn’t send any answers… I also have a similar cpu model ( Not the same than the one with the problem ) this one is a little older but in the other cpu having 4 serial ports ( /dev/ttyS0-3 ) everything is working fine… I already checked the kernel and the drivers are there… I don’t know what else to do…

I tried testing different devices, a printer, a display, etc… I have tried making changes in the BIOS different BIOS versions as well, upgrading the kernel to Linux 5 and OS to ubuntu 18.04 but it still didn’t work so i went back to ubuntu 16.04 because i wanted to work with that OS from the beginning

If i reinstall CentOS 5 or 6.5 the ports start working fine again, In ubuntu they get recognised if i make a dmesg | grep tty the output shows the three serial ports and if i try setserial -g /dev/ttyS* they appears normally but any device connected to them is working… what could it be?

“No Route to host” for certain ports via certain IPs

I have this weird situation whereby I have a mysql server running on my laptop, and I have a VM that is on this laptop.

I have noticed that I can, through the VM, ssh to the host via host-only ip (192.168.56.1) but I cannot connect to the port 3306. BUT it works if I use the LAN IP address of the host!

I used the “nc -vz” command and I get the following output from the VM:

[root@portal42 portal]# nc -vz 192.168.56.1 3306 Ncat: Version 7.50 ( https://nmap.org/ncat ) Ncat: No route to host. [root@portal42 portal]# nc -vz 192.168.178.241 3306 Ncat: Version 7.50 ( https://nmap.org/ncat ) Ncat: Connected to 192.168.178.241:3306. Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds. [root@portal42 portal]# nc -vz 192.168.178.66 3306 Ncat: Version 7.50 ( https://nmap.org/ncat ) Ncat: Connected to 192.168.178.66:3306. Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds. [root@portal42 portal]# nc -vz 192.168.178.66 24800 Ncat: Version 7.50 ( https://nmap.org/ncat ) Ncat: Connection refused. [root@portal42 portal]# nc -vz 192.168.178.66 24801 Ncat: Version 7.50 ( https://nmap.org/ncat ) Ncat: Connection refused. [root@portal42 portal]# nc -vz 192.168.178.66 3307 Ncat: Version 7.50 ( https://nmap.org/ncat ) Ncat: Connection refused. [root@portal42 portal]# nc -vz 192.168.56.1 3307 Ncat: Version 7.50 ( https://nmap.org/ncat ) Ncat: No route to host. 

(As you can see, if I have no service running, it just states ‘connection refused’ from an IP I would have had access through normally, and that is normal.)

I also have a machine on the LAN from which i tried the same, and in that case, the nz command using the LAN IP of the laptop, it gives me ‘No Route to host’ BUT only for certain ports: port 80, 25 and 22 work, but 24800 and 3306 do not, although i do have services working on those ports. (…66 is the wifi and …241 is the wired (I have both attached).

mau@mail:~$   nc -vz 192.168.178.66 61616 nc: connect to 192.168.178.66 port 61616 (tcp) failed: No route to host 1 mau@mail:~$   nc -vz 192.168.178.66 3306 nc: connect to 192.168.178.66 port 3306 (tcp) failed: No route to host 1 mau@mail:~$   nc -vz 192.168.178.66 24800 nc: connect to 192.168.178.66 port 24800 (tcp) failed: No route to host 1 mau@mail:~$   nc -vz 192.168.178.66 80 Connection to 192.168.178.66 80 port [tcp/http] succeeded! mau@mail:~$   nc -vz 192.168.178.66 22 Connection to 192.168.178.66 22 port [tcp/ssh] succeeded! 1 mau@mail:~$   nc -vz 192.168.178.66 25 Connection to 192.168.178.66 25 port [tcp/smtp] succeeded! mau@mail:~$   nc -vz 192.168.178.241 3306 nc: connect to 192.168.178.241 port 3306 (tcp) failed: No route to host 

I have disabled ufw, I have flushed iptables on my laptop:

sudo iptables -L -n [sudo] password for mau:  Chain INPUT (policy ACCEPT) target     prot opt source               destination           Chain FORWARD (policy ACCEPT) target     prot opt source               destination           Chain OUTPUT (policy ACCEPT) target     prot opt source               destination          

Also, my mysql is with bind_address=0.0.0.0

and ufw disabled

sudo service ufw status ‚óŹ ufw.service - Uncomplicated firewall    Loaded: loaded (/lib/systemd/system/ufw.service; enabled; vendor preset: enabled)    Active: inactive (dead) since Tue 2019-06-25 21:30:35 CEST; 17h ago      Docs: man:ufw(8)   Process: 339 ExecStart=/lib/ufw/ufw-init start quiet (code=exited, status=0/SUCCESS)   Process: 20404 ExecStop=/lib/ufw/ufw-init stop (code=exited, status=0/SUCCESS)  Main PID: 339 (code=exited, status=0/SUCCESS)  Jun 24 22:40:18 mau-Precision-7520 systemd[1]: Started Uncomplicated firewall. Jun 25 21:30:35 mau-Precision-7520 systemd[1]: Stopping Uncomplicated firewall... Jun 25 21:30:35 mau-Precision-7520 systemd[1]: ufw.service: Succeeded. Jun 25 21:30:35 mau-Precision-7520 systemd[1]: Stopped Uncomplicated firewall. Warning: Journal has been rotated since unit was started. Log output is incomplete or unavailable. 

there are no indications in the logs what so ever and aparmor is also removed

This problem happened after an upgrade of ubuntu but I cannot figure out what the issue is!

Any help please, it is 5 days that I noticed this and I cannot fathom what can be the problem!

Thanks

Fail2ban: Ban ip on all ports exept HTTP[S] (or group of ports)

My server currrently has very strict fail2ban rules, which permanently and persistently ban any ip that fails to login once on all ports. This might seem overkill, but most ports are “private” ports (meaning only I should access them).

Since my server runs a public website, ips should not be banned on HTTP & HTTPS, I also have setup an web interface to unban my ip, in case I lock myself out, which I then need to be able to access.

I don’t have much expirence with firewalls & iptables and am currently using action.d/iptables-allports.conf with persistent bans.

How can I configure an action to ban the ip on all ports except for “public ports” or ban the ip on all “private ports” (given a static list of public / private ports)?

Thanks in advance. -Minding

Network Policy Server + RADIUS not listening on any ports for Windows Server 2019

Trying to setup Windows Server 2019 as a RADIUS server. However, after configuring everything, “netstat -b” shows that the machine is not listening on any of the expected RADIUS ports (1812, 1645, 1813, 1646).

  1. Installed the “Network Policy and Access Services” role
  2. Followed the “Configure VPN or Dial-up” wizard RADIUS wizard

  3. Confirmed RADIUS configuration: RADIUS config

  4. Confirmed “Network Policy Server” ports: NPS ports

  5. Confirmed the “Network Policy Server” service is running.

Result: “netstat -b” shows that the machine is not listening on any of the expected RADIUS ports (1812, 1645, 1813, 1646).

Have tried with no luck:

  1. Rebooting
  2. Restarting the “Network Policy Server” service

Reverse SSH – How to limit ports on server side

My system is SSH client that use the following SSH command in order to create a tunnel:

ssh -R 0:localhost:80 -TN -p 22 user@pass 

I use “0” so the port will be chosen randomly by the SSH server. Now i have the requirement that the port range need to be limited (to the range 4000 – 4100) but as the system’s software can’t be changed (A limitation i have) – I must to do this change in SSH server side. Is there anything I can do in SSH server side?

VirtualBox: I can’t access from the guest (Windows 10 trial) serial ports (COM) from the host (Xubuntu 18.04)

  • Backstory: One day I’m on Ubuntu and my tablet bricked so hard that I could not get it to boot into recovery but I got it to boot into EDL so now I just need some images and a program to load them, unfortunately, there isn’t such thing for Ubuntu. But there is VirtualBox right? I installed it then installed Windows 10 on it and installed XiomiFlash on Windows 10.

One

BIG

PROBLEM

I can’t get the COM ports working to flash the firmware on my tablet (As you may or may not know the images are flashed through a serial port) So what do I do now, I don’t want to install Windows 10 on my PC I like Ubuntu. Is accessing serial ports from the guest even possible?

Postfix combinations of TLS/STARTTLS and ports 465/587

I’m setting up a barebones Postfix mail server and have this observation:

  • TLS works on port 465
  • STARTTLS works on port 587
  • TLS does NOT work on port 587
  • STARTTLS does NOT work on port 465

Is this normal SMTP behavior or is it specific to Postfix? I was reading that using port 465 was discouraged and not RFC compliant.

https://www.mailgun.com/blog/which-smtp-port-understanding-ports-25-465-587

Is it then not possible to be RFC compliant on port 587, AND use TLS instead of STARTTLS?