Install: Check for valid upstream DNS IP addresses excludes IPv6

[voltagex]

https://discourse.pi-hole.net/t/setdns-in-basic-install-sh-does-not-support-ipv6-ipv6-upstream-dns-means-i-cant-finish-the-install/67890

Versions

• Pi-hole: not installed yet
• AdminLTE: not installed yet
• FTL: not installed yet

Platform

• OS and version: Debian Trixie aarch64

• Platform: VM

Expected behavior

I am able to install Pi-Hole with PIHOLE_SKIP_OS_CHECK=true and upstream DNS set to IPv6 address/es

A clear and concise description of what you expected to happen.

Actual behavior / bug

A clear and concise description of what the bug is.

Steps to reproduce

Steps to reproduce the behavior:

1. curl -sSL https://install.pi-hole.net | sudo PIHOLE_SKIP_OS_CHECK=true bash
2. Select custom upstream DNS
3. Enter 2001:0DB8::123:456 (NOTE: this is an IPv6 documentation address and won't work as a real server!)
4. See error

[voltagex]

Note that the UI once Pi-Hole is installed seems to work

[pralor-bot]

This issue has been mentioned on Pi-hole Userspace. There might be relevant details there:

https://discourse.pi-hole.net/t/setdns-in-basic-install-sh-does-not-support-ipv6-ipv6-upstream-dns-means-i-cant-finish-the-install/67890/1

[yubiuser]

Thanks for this report.

There are two issues here: one is expected and one is a bug.
Expected is that you need to overwrite the OS check - Trixi is not an supported OS.

---

The IPv6 issue is a real bug. As you already found out, we need to check also for valid IPv6 addresses at

pi-hole/automated install/basic-install.sh

Line 978 in 19bfa08

if ! valid_ip "${PIHOLE_DNS_1}" || [[ ! "${PIHOLE_DNS_1}" ]]; then

[DL6ER]

Should be fixed by #5560