Should I block port 138?

Port 138 is utilized by NetBIOS Datagram service. Enabling NetBIOS services provide access to shared resources like files and printers not only to your network computers but also to anyone across the internet. Therefore it is advisable to block port 138 in the Firewall.

How do I block port 139?

Step 1: Open the Control Panel Step 2: Click on Windows Firewall/ Windows Defender firewall Step 3: Navigate to advanced settings. Step 4:Right click on inbound rules and click on new rule. Step 6:Select port and press next Step 7:Specify the port 139 under specific local ports, select TCP and press next.

What is NetBIOS port used for?

NetBIOS stands for Network basic input output system and is used in Windows for its file and printer sharing. From Wikipedia: It provides services related to the session layer of the OSI model allowing applications on separate computers to communicate over a local area network.

Should NetBIOS be blocked?

Enabling NetBIOS services provide access to shared resources like files and printers not only to your network computers but also to anyone across the internet. Therefore it is advisable to block port 137 in the Firewall.

What are ports 137 and 138 used for?

Ports 137, 138, and 139 are used by NetBIOS, which does not support IPv6. CIFS is required for Windows file service. You can disable CIFS by issuing the cifs terminate command on your storage system console.

How to Allow Block a Port Number Through Windows Firewall

Is it safe to have port 139 open?

If you are on Windows-based network that is running NetBios, it is perfectly normal to have port 139 open in order to facilitate that protocol. If you are not on a network using NetBios, there is no reason to have that port open.

What is the problem with 139 port?

Port 139 is used for File and Printer Sharing but happens to be the single most dangerous Port on the Internet. This is so because it leaves the hard disk of a user exposed to hackers.

What application uses port 138?

Port 138 is utilized by NetBIOS Datagram service. Enabling NetBIOS services provide access to shared resources like files and printers not only to your network computers but also to anyone across the internet.

Is NetBIOS secure?

Vulnerabilities in Windows Host NetBIOS to Information Retrieval is a Low risk vulnerability that is one of the most frequently found on networks around the world. This issue has been around since at least 1990 but has proven either difficult to detect, difficult to resolve or prone to being overlooked entirely.

Is port 139 still needed for SMB?

As such, SMB requires network ports on a computer or server to enable communication to other systems. SMB uses either IP port 139 or 445.

How do I disable NetBIOS?

Right-click Local Area Connection, and then click Properties. Select Internet Protocol Version 4 (TCP/IPv4), click Properties, and then click Advanced. Click the WINS tab, and in the NETBIOS setting section, click Disable NETBIOS over TCP/IP. Click OK to close the properties windows.

Is NetBIOS needed?

NetBIOS is legacy and you only need it if you are using old applications or old versions of Windows that require it or use WINS. If your running applications or OS's that require it still, NetBIOS is probably not the real problem here.

Is SMB secure?

SMB Encryption. SMB Encryption provides end-to-end encryption of SMB data and protects data from eavesdropping occurrences on untrusted networks. You can deploy SMB Encryption with minimal effort, but it may require small additional costs for specialized hardware or software.

What is the protocol for port 139?

Port 139 Details. NetBIOS is a protocol used for File and Print Sharing under all current versions of Windows.

What ports are vulnerable to Wannacry?

The best approach is to explicitly block all inbound access to TCP 445 at the top of the rule base to avoid mistakenly opening it up by lower rules. We also recommend blocking port 445 on internal firewalls to segment your network – this will prevent internal spreading of the ransomware.

What are vulnerable ports?

What happens if I block port 445?

Blocking TCP 445 will prevent file and printer sharing and also other services such as DHCP (dynamic host configuration protocol) which is frequently used for automatically obtaining an IP address from the DHCP servers used by many corporations and ISPs(Internet Service Providers) will stop functioning.

What type of traffic is normally seen over UDP port 137?

Protocol dependencies

UDP: Typically, NBNS uses UDP as its transport protocol. The well known UDP port for NBNS traffic is 137. TCP: NBNS can also use TCP as its transport protocol for some operations, although this might never be done in practice. The well known TCP port for NBNS traffic is 137.

Is NetBIOS needed for SMB?

On Windows, SMB can run directly over TCP/IP without the need for NetBIOS over TCP/IP. This will use, as you point out, port 445 .

Is NetBIOS deprecated?

Amazingly, NetBIOS is actually still used in the trust creation process, even though Microsoft has officially “deprecated” NetBIOS in versions of Windows from 2000 on. So if you disable NETBIOS on your domain controllers, you won't be able to establish a forest trust between two Windows Server 2003 forests.

Is it safe to disable NetBIOS?

It is also recommended to disable NetBIOS over TCP/IP to improve network performance. Disabling NetBIOS over TCP/IP is especially recommended on Hyper-V and Windows Server cluster hosts with dedicated NICs used for traffic, such as iSCSI and Live Migration.