Udp port 137

I had a newWindows 2008R2 server with IIS7 and began to see outgoing UDP packets on port 137 being blocked and logged by our firewall. It was intermittently happening when a user would connect to our web server, with no apparent pattern. I finally traced it back to the Performance Monitor.

The Test-NetConnection cmdlet displays diagnostic information for a connection. It supports ping test, TCP test, route tracing, and route selection diagnostics. Depending on the input parameters, the output can include the DNS lookup results, a list of IP interfaces, IPsec rules, route/source address selection results, and/or confirmation of connection establishment. Jul 15, 2019 · There were no connections to any Internet IP address on UDP port 137, just the normal LAN side traffic on that port. More Information Part 4 -Windows 7 Wondering if this was a Windows 10 thing only, I installed the Brave browser on a Windows 7 computer. Oct 21, 2019 · UDP messages are generally broadcast over a network to anyone who is listening on the specified UDP port. This makes it perfect for housekeeping type messages that relate to running the network itself. It’s also perfect for voice-over-IP streaming, online video games and streaming broadcasts. 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. Example traffic 137 . NETBIOS-NS . NETBIOS name service . 138 . NETBIOS-DGM . NETBIOS datagram service . 139 . NETBIOS-SSN . NETBIOS session service . 161 . SNMP . Simple Network Management Protocol Q/R . 162 . SNMP-TRAP . Simple Network Management Protocol traps . 512 . rexec . UNIX rexec (Control) 513 . TCP—rlogin UDP—rwho . TCP—UNIX rlogin UDP—UNIX 137/udp open netbios-ns 138/udp open|filtered netbios-dgm 139/udp open|filtered netbios-ssn 443/udp open|filtered https 445/udp open|filtered microsoft-ds nmap results of machine not found Nmap scan report for xx.xx.xx.55 Host is up (0.00s latency). PORT STATE SERVICE 135/udp open|filtered msrpc 137/udp open|filtered netbios-ns 138/udp open

UDP scan works by sending a UDP packet to every targeted port. For most ports, this packet will be empty (no payload), but for a few of the more common ports a protocol-specific payload will be sent. Based on the response, or lack thereof, the port is assigned to one of four states, as shown in Table 5.3 .

The thing is - it happens from time to time only and make the whole network completely unuseable. The traffic is on all ports and blocking all devices. Network bandwidth on every port is down to 3-4 Mbit/s. I then disable the WAN port inside the pfSense and re-enable it - no more packages, troughput back to normal. UDP on port 137 is Windows NetBIOS Name Service, typically Windows file sharing (on a LAN).. passing System Names, File Shares, etc. Unexplained outbounds on UDP 137, in volume, might indicate a possible worm infection (trying to seek other victims). This being a possibility, you should update your AV definitions & run a scan. Oct 10, 2018 · This check udp port article will talk about the User Datagram Protocol, what is used for and the tool to use it. User Datagram Protocol (UDP) is like a send and forget protocol. To check if the UDP port is open or not, you should receive a response from the port.

UDP Port 137 may use a defined protocol to communicate depending on the application. A protocol is a set of formalized rules that explains how data is communicated over a network. Think of it as the language spoken between computers to help them communicate more efficiently.

The remote host is listening on UDP port 137 or TCP port 445, and replies to NetBIOS nbtscan or SMB requests. Note that this plugin gathers information to be used in other plugins, but does not itself generate a report. If you're still trying your own then you should change the protocol (-p) to read "udp", watch the d/sports, and add an interface, or it'll activate this rule on any interface unless overridden, but that's a minor detail. For instance: /sbin/iptables -A INPUT -i eth#-p udp--dport 137 -j DROP /sbin/iptables -A OUTPUT -i eth#-p udp--sport 137 -j DROP This setting opens UDP ports 137 and 138, and TCP ports 139 and 445. This is required for the IPC$ and ADMIN$ shares to be available. Administrative access to these shares is required. (If using a local account to deploy/scan target computers, please see this article for additional configuration settings). Windows Firewall: Allow ICMP exceptions The thing is - it happens from time to time only and make the whole network completely unuseable. The traffic is on all ports and blocking all devices. Network bandwidth on every port is down to 3-4 Mbit/s. I then disable the WAN port inside the pfSense and re-enable it - no more packages, troughput back to normal. UDP on port 137 is Windows NetBIOS Name Service, typically Windows file sharing (on a LAN).. passing System Names, File Shares, etc. Unexplained outbounds on UDP 137, in volume, might indicate a possible worm infection (trying to seek other victims). This being a possibility, you should update your AV definitions & run a scan. Oct 10, 2018 · This check udp port article will talk about the User Datagram Protocol, what is used for and the tool to use it. User Datagram Protocol (UDP) is like a send and forget protocol. To check if the UDP port is open or not, you should receive a response from the port. Port numbers in computer networking represent communication endpoints. Ports are unsigned 16-bit integers (0-65535) that identify a specific process, or network service. IANA is responsible for internet protocol resources, including the registration of commonly used port numbers for well-known internet services.