coredns/plugin/bufsize

bufsize

Name

bufsize - sizes EDNS0 buffer size to prevent IP fragmentation.

Description

bufsize limits a requester's UDP payload size.
It prevents IP fragmentation so that to deal with DNS vulnerability.

Syntax

bufsize [SIZE]

[SIZE] is an int value for setting the buffer size.
The default value is 512, and the value must be within 512 - 4096.
Only one argument is acceptable, and it covers both IPv4 and IPv6.

Examples

. {
    bufsize 512
    forward . 172.31.0.10
    log
}

If you run a resolver on 172.31.0.10, the buffer size of incoming query on the resolver will be set to 512 bytes.

Considerations

For now, if a client does not use EDNS, this plugin adds OPT RR.