~/dnsniffer/issuers/cisco-systems·rank #71
$ dnsniffer count --issuer cisco-systems --active

How many domains does Cisco Systems secure?

2,268

active domains whose current TLS certificate was issued by Cisco Systems, as of 0.00% of all attributed domains.

# rank #71 of all CAs# all records held: 2,286# subdomains: 6,350# intermediates: 2# United States
~/issuers/cisco-systems/history·active domains
2,268
domains secured by Cisco Systems on 2026-08-31 · +341 (+17.70%) since 2025-06-30
2K2K2K2K2K2025-06-30: 1,927 active2025-07-31: 2,111 active2025-08-31: 2,112 active2025-09-30: 2,117 active2025-10-31: 2,117 active2025-11-30: 2,117 active2025-12-31: 2,147 active2026-01-31: 2,201 active2026-02-28: 2,201 active2026-03-31: 2,201 active2026-04-30: 2,230 active2026-05-31: 2,258 active2026-06-30: 2,268 active2026-07-31: 2,270 active2026-08-31: 2,268 active2025-06-302026-08-31

# y-axis starts at 2K, not zero — domain counts move by fractions of a percent a day. Dashed segments are estimated: reconstructed from certificate first-seen dates before daily snapshots began, not measured on the day.

# change over time
30 days
-0.09%
-2 domains
90 days
+0.44%
+10 domains
1 year
+7.39%
+156 domains
# intermediate CAs
Intermediate certificate authorities operating under Cisco Systems, with the number of active domains each currently secures.
intermediatecountrydomains
HydrantID Server CA O1United States2,268
Cisco Meraki CAUnited States0
# faq
? How many domains does Cisco Systems secure?
Cisco Systems is the certificate authority for 2,268 active domains as of August 31, 2026 — 0.00% of every domain DNSniffer can attribute to an issuer.
? Is Cisco Systems gaining or losing market share?
The number of domains secured by Cisco Systems has grown by 7.39% over the last year (+156 domains).
? Which intermediate CAs does Cisco Systems sign from?
We have seen 2 intermediates under Cisco Systems, the busiest being “HydrantID Server CA O1” with 2,268 domains. The full list, with per-intermediate counts, is on this page.
? Where does this number come from?
DNSniffer ingests Certificate Transparency logs continuously and records the issuer of the most recent certificate seen for each domain, then snapshots the per-issuer count once a day. It measures how much of the live web a CA currently secures, not how many certificates it has issued over its lifetime.