DNS SOA Serial bug

[schamberg97]

• Version: 11.16.0 & 12.6.0
• Platform: macOS 10.14.5 & Ubuntu 18.04.2 LTS (4.15.0-54-generic)
• Subsystem: dns

Bug description

dns.resolveSoa may produce unexpected "serial" results, when the serial does not follow the YYYYMMDDHH format (or if the serial reaches a certain date ;)

Code sample

var dns = require("dns")
dns.resolveSoa("some.host", function(e,o) {console.log(o)})

Expected results

{
nsname: 'ns1.some.host',
hostmaster: 'hostmaster.some.host',
serial: 4294867295,
refresh: 86400,
retry: 7200,
expire: 1209600,
minttl: 3000
}

Actual results

{
...
serial: -100001, // this is weird
...
}

Observations

After some tests, it appears the lowest serial number under which this issue appears is 2147483648 (something to do with dates?)