Is UDP on IPv6 implemented?
I’m unable to connect to a UDP port exposed on the load balancer IPv6 address.
And I’m also unable to do any UDP connections inside the VM/container to outside IPv6 addresses.
Here is a test done with dig inside a fly VM/container:
bash-5.0# dig @2001:4860:4860::8888 google.com
; <<>> DiG 9.16.6 <<>> @2001:4860:4860::8888 google.com
; (1 server found)
;; global options: +cmd
;; connection timed out; no servers could be reached
bash-5.0# dig @2001:4860:4860::8888 google.com +tcp
; <<>> DiG 9.16.6 <<>> @2001:4860:4860::8888 google.com +tcp
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 49548
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;google.com. IN A
;; ANSWER SECTION:
google.com. 299 IN A 216.58.215.46
;; Query time: 12 msec
;; SERVER: 2001:4860:4860::8888#53(2001:4860:4860::8888)
;; WHEN: Thu Feb 04 16:35:35 UTC 2021
;; MSG SIZE rcvd: 55
As you can see it works perfectly in TCP but not in UDP.