We see some significant variation between the two servers: clients of B appear more likely use the DAYTIME protocol and to emit NTP requests from UDP port
The IPv6 address acquired from Teredo server by the Teredo client is mapped as public IPv4 address and UDP port
numbers are encoded in the IPv6 address.
A common capture filter to only capture standard BACnet/IP packets would be "udp port
Bonjour is a networking protocol that sends and receives network packets on UDP port
HTTP uses TCP port 80; DNS normally uses UDP port
* Interactive: telnet, finger, rwho, rlogin (TCP ports 23, 79, 513, UDP port
However, by using mechanisms such as Diffserv, VLAN Tagging, and UDP port
prioritization, traffic can be prioritized for transport across the IP network to deliver a QoS approaching that of SONET networks.
It uses the Layer 2 VLAN tag field or the Layer 3 IP TOS/DS field, and the Layer 4 TCP and UDP port
numbers for packet prioritization to drop non-critical packets from the data stream.
Intrusion detection includes existing URL vulnerabilities within Windows' IIS 3.0/4.0, TCP and UDP port
sweeps and enhanced stateful packet inspection intrusion-detection algorithms.
Though it may be a conservative approach, it requires reconfiguration of the firewall to allow VPN traffic through PPTP (TCP port 1723 and IP protocol id 47) and/or IPSEC (UDP port
4002 and IP protocol id 50).
So-called Layer 4 switches actually examine, not just the Layer 2 network address and the Layer 3 IP address, but they may also look at the TCP or UDP port
associated with each packet so that different streams of packets can be treated differently.
Another measure is to disable SMBv1 and block all versions of SMB (EternalBlue) at the network boundary by blocking TCP port 445 with related protocols on UDP ports
137-138 and TCP port 139, for all boundary devices."