Yes — crestlinepayments.com has IPv6.

Has both IPv4 (A) and IPv6 (AAAA) addresses.

IPv6 readiness

Website, mail and DNS all work over IPv6.

Website over IPv6 crestlinepayments.com has 2 IPv6 addresses and answers on every one we tested. ✓ 2606:4700:3030::ac43:d091 answers · 443✓ 2606:4700:3033::6815:4d88 answers · 443	yes
www over IPv6 www.crestlinepayments.com has 2 IPv6 addresses and answers on every one we tested. ✓ 2606:4700:3030::ac43:d091 answers · 443✓ 2606:4700:3033::6815:4d88 answers · 443	yes
Mail servers (MX) have IPv6 Every mail server has an AAAA record. route1.mx.cloudflare.net ✓route3.mx.cloudflare.net ✓route2.mx.cloudflare.net ✓	yes
Nameservers have IPv6 2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up. fiona.ns.cloudflare.com ✓jaziel.ns.cloudflare.com ✓	yes

HTTPS over IPv6 · not part of the grade yet
Answered over IPv6 with a server error (HTTP 525) — can't tell whether that's specific to IPv6.

https://crestlinepayments.com/ via 2606:4700:3030::ac43:d091 → 525

Nothing keeping you from an A

Nothing to fix
Show it off: add the badge to your README.
[![IPv6](https://aaaa.bot/badge/crestlinepayments.com.svg)](https://aaaa.bot/crestlinepayments.com)

Check again

crestlinepayments.com Has IPv6

A (IPv4)	104.21.77.136 172.67.208.145
AAAA (IPv6)	2606:4700:3030::ac43:d091 2606:4700:3033::6815:4d88

www.crestlinepayments.com Has IPv6

A (IPv4)	172.67.208.145 104.21.77.136
AAAA (IPv6)	2606:4700:3030::ac43:d091 2606:4700:3033::6815:4d88

Browsers on dual-stack networks will usually pick IPv6 here (the "Happy Eyeballs" algorithm races both and prefers v6).

Copy the evidence — a citation-ready record of this measurement

IPv6 measurement: crestlinepayments.com
Measured 2026-11-10 15:18:05 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    104.21.77.136, 172.67.208.145
AAAA (IPv6): 2606:4700:3030::ac43:d091, 2606:4700:3033::6815:4d88
www AAAA:    2606:4700:3030::ac43:d091, 2606:4700:3033::6815:4d88

Readiness grade A: Website, mail and DNS all work over IPv6.
- Website over IPv6: crestlinepayments.com has 2 IPv6 addresses and answers on every one we tested.
    2606:4700:3030::ac43:d091: answers (TCP 443)
    2606:4700:3033::6815:4d88: answers (TCP 443)
- www over IPv6: www.crestlinepayments.com has 2 IPv6 addresses and answers on every one we tested.
    2606:4700:3030::ac43:d091: answers (TCP 443)
    2606:4700:3033::6815:4d88: answers (TCP 443)
- Mail servers (MX) have IPv6: Every mail server has an AAAA record.
- Nameservers have IPv6: 2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up.

Reachability = a TCP connection opened on port 443 (or 80).

HTTPS over IPv6 (not graded): Answered over IPv6 with a server error (HTTP 525) — can't tell whether that's specific to IPv6.
    https://crestlinepayments.com/ via 2606:4700:3030::ac43:d091 -> HTTP 525, certificate: valid
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/Z8bJuhjgyh

Permanent link: aaaa.bot/r/Z8bJuhjgyh · How we measure

Checked 2026-11-10 15:18:05 UTC. Full DNS report: dns.pizza/domain/crestlinepayments.com · Age, certificate and blocklists: how.is/crestlinepayments.com · JSON: /api/v1/crestlinepayments.com