Travis-CI, many warnings, WARN javax.jmdns.impl.*

Hello,
When building with Travis-CI a lot of warnings are visible. The warnings disappear when blocking incoming network packets.

This is an example of the warnings:
```
[SocketListener(travis-job-f5c57bf3-d337-4ba0-94cc-4d57fcd3af06-c-eco-emissary-99515-internal.local.)] WARN javax.jmdns.impl.DNSIncoming$MessageInputStream - Bad domain name: possible circular name detected. Bad offset: 0x3fff at 0x73
[SocketListener(travis-job-f5c57bf3-d337-4ba0-94cc-4d57fcd3af06-c-eco-emissary-99515-internal.local.)] WARN javax.jmdns.impl.constants.DNSRecordType - Could not find record type for index: 65535
[SocketListener(travis-job-f5c57bf3-d337-4ba0-94cc-4d57fcd3af06-c-eco-emissary-99515-internal.local.)] WARN javax.jmdns.impl.DNSIncoming - Could not find record type: dns[query,10.30.3.52:5353, length=117, id=0x0]
0: 0000000000010000 000100004d747261 7669732d6a6f622d 6635633537626633 ........ ....Mtra vis-job- f5c57bf3
20: 2d643333372d3462 61302d393463632d 3464353766636433 616630362d632d65 -d337-4b a0-94cc- 4d57fcd3 af06-c-e
40: 636f2d656d697373 6172792d39393531 352d696e7465726e 616c056c6f63616c co-emiss ary-9951 5-intern al.local
60: 0000ff0001c00c00 0100010000000900 040a1e0334 ........ ........ ....4
[SocketListener(travis-job-f5c57bf3-d337-4ba0-94cc-4d57fcd3af06-c-eco-emissary-99515-internal.local.)] WARN javax.jmdns.impl.constants.DNSRecordClass - Could not find record class for index: 65535
```

Firewalling the Travis-Virtual-Machine from incoming packets gives a regular build output:
```
- sudo iptables -P INPUT DROP
- sudo iptables -P FORWARD DROP
- sudo iptables -P OUTPUT ACCEPT
- sudo iptables -A INPUT -i lo -j ACCEPT
- sudo iptables -A OUTPUT -o lo -j ACCEPT
- sudo iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
```

A working example configuration for Travis-CI is here: [Travis-CI](https://travis-ci.com/Torxgewinde/Desk-Lamp-Alternative-Firmware/jobs/210099319/config)

According to the warnings the issue seems to be related to jmdns. Can these warnings be resolved or suppressed?

Kind regards,
Tom

Start by reproducing the warnings in Travis-CI using the linked configuration and inspect the javax.jmdns.impl.DNSIncoming, DNSRecordType, and DNSRecordClass messages. Compare the behavior with the listed iptables rules and determine whether malformed incoming packets should be handled differently or only logged less noisily. Done means Travis builds without these warnings while normal JmDNS behavior is preserved.

Written by the indexing model from the issue text.