Yes — cisco.com has IPv6.

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

IPv6 readiness

Website, mail and DNS all work over IPv6.

Website over IPv6 cisco.com has an AAAA record and answers on it. ✓ 2001:420:1101:1::185 answers · 443	yes
www over IPv6 www.cisco.com has 2 IPv6 addresses and answers on every one we tested. ✓ 2600:1408:5400:e99::b33 answers · 443✓ 2600:1408:5400:e93::b33 answers · 443	yes
Mail servers (MX) have IPv6 Every mail server has an AAAA record. alln-mx-01.cisco.com ✓rcdn-mx-01.cisco.com ✓aer-mx-01.cisco.com ✓	yes
Nameservers have IPv6 5 of 5 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up. ns2.cisco.com ✓a3-64.akam.net ✓ns3.cisco.com ✓ns1.cisco.com ✓a28-64.akam.net ✓	yes

HTTPS over IPv6 · not part of the grade yet
Loads over IPv6 with a valid certificate after 1 redirect: HTTP 200.

https://cisco.com/ via 2001:420:1101:1::185 → 302https://www.cisco.com/ via 2600:1408:5400:e99::b33 → 200

works

Nothing keeping you from an A

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

Check again

cisco.com Has IPv6

A (IPv4)	72.163.4.185
AAAA (IPv6)	2001:420:1101:1::185

www.cisco.com Has IPv6

Alias of	www.cisco.com.akadns.net → wwwds.cisco.com.edgekey.net → e2867.dsca.akamaiedge.net
A (IPv4)	23.35.28.110
AAAA (IPv6)	2600:1408:5400:e99::b33 2600:1408:5400:e93::b33

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: cisco.com
Measured 2026-10-30 19:04:31 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    72.163.4.185
AAAA (IPv6): 2001:420:1101:1::185
www AAAA:    2600:1408:5400:e99::b33, 2600:1408:5400:e93::b33

Readiness grade A: Website, mail and DNS all work over IPv6.
- Website over IPv6: cisco.com has an AAAA record and answers on it.
    2001:420:1101:1::185: answers (TCP 443)
- www over IPv6: www.cisco.com has 2 IPv6 addresses and answers on every one we tested.
    2600:1408:5400:e99::b33: answers (TCP 443)
    2600:1408:5400:e93::b33: answers (TCP 443)
- Mail servers (MX) have IPv6: Every mail server has an AAAA record.
- Nameservers have IPv6: 5 of 5 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): Loads over IPv6 with a valid certificate after 1 redirect: HTTP 200.
    https://cisco.com/ via 2001:420:1101:1::185 -> HTTP 302, certificate: valid
    https://www.cisco.com/ via 2600:1408:5400:e99::b33 -> HTTP 200, certificate: valid
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/nLlPFjrvV6

Permanent link: aaaa.bot/r/nLlPFjrvV6 · How we measure

Checked 2026-10-30 19:04:31 UTC — one of the top 1,000 sites, re-checked weekly. Re-check now. Full DNS report: dns.pizza/domain/cisco.com · JSON: /api/v1/cisco.com