Caught in the company office environment, found that there are a large number of LLMNR DNS packets, destination port 5355 or 5353, PC hang under a layer 3 switches, the source packet is layer 3 switches under a port of PC, the problem is, layer 3 switches to deal with this kind of multicast packets, is layer 3 switches forward continued to interface to the router and forwarded to the corresponding ports in the group?

CodePudding user response:

also the LLMNR is what message, what conditions will issue?

CodePudding user response:

CodePudding user response:

We are through the baidu to learn together:
Link local multicast name resolution (LLMNR) is a protocol based on domain name system (DNS) packet format, IPv4 and IPv6 hosts can by this agreement to the same local host name resolution execution on a link, the Windows operating system, embedded support from Windows Vista start Linux system also through systemd implements this protocol, LLMNR defined in RFC 4795,
Other information too much, skip

Simple to summarize:
The agreement is: local link range of DNS queries
Encapsulation protocol: UDP port number: the purpose of the UDP packet 5355
The purpose of the multicast address: 224.0.0.252
Scope of multicast scope: local link
Send LLMNR conditions: the host in your DNS cache, main use DNS, secondary DNS are failed, the sending LLMNR, locally link range of DNS queries,