Wait it out
Confirmed outages need fixing on the provider's side. Nothing you do locally will change the result.
Website · caltech.edu
Is Caltech down?
caltech.edu
education
US
DOWN
0.00% uptimelast 30 days
See full history →
30 days agocollecting data · 1/30 daystoday
Checked 2s ago
3/4 probe methods returned data
every 5 min · HTTP probe
direct probe, not crowd-reported
Per-method results
HTTP/1.1
DOWN
-
UNABLE_TO_VERIFY_LEAF_SIGNATURE
HTTP/2
PENDING
130 ms
ERR_HTTP2_STREAM_CANCEL
Browser UA
DOWN
-
UNABLE_TO_VERIFY_LEAF_SIGNATURE
curl HEAD
DOWN
-
UNABLE_TO_VERIFY_LEAF_SIGNATURE
HTTP details
- HTTP status
- -
- Response time
- 137 ms
- Region consensus
- 0/4 reachable
- 24h success rate
- 0% (0/1 probes)
90-day uptime
0.00%
≥99.9%
≥99%
≥95%
<95%
no data
Network
- Host
- caltech.edu
- Port
- 443
- Transport
- HTTPS
What this means
Caltech failed all 4 probe methods.
This is a confirmed outage. Most users worldwide are affected. Check the provider's status page or socials for an ETA, no client-side fix will help.
What to try next
Check related
Scroll to related services below to see if the outage is provider-wide.
Re-run
Reload this page to re-probe, we check on-demand as well as on the 5-minute cadence.
FAQ
Why is Caltech down right now?
Outages typically come from CDN/DNS issues, failed deploys, regional routing problems, or DDoS. We can't see Caltech's internal cause, we only confirm reachability from each probe method. If all 4 probe methods failed, it's a confirmed outage on Caltech's side. If only some failed, Caltech is up but blocking or mishandling a specific request type.
Is Caltech down for everyone or just me?
Look at the probe-method grid above. If every probe method succeeded, the issue is local to your network, flush DNS, switch networks, or disable your VPN. If two or more probe methods failed, the outage is on Caltech's side.
How often does isitdown.io re-check Caltech?
Every 5 minutes via background HTTP probes using 4 independent probe methods. You can also re-run on demand by reloading, the verdict above reflects the latest probe.
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Related · education
Methodology
- Probe
- We send a GET request to the target URL with each probe method and time the full response.
- Counts as DOWN
- Every probe method fails the request (connect refused, DNS error, timeout, or HTTP 5xx).
- Counts as DEGRADED
- At least one probe method succeeds but at least one fails, the site is up but blocking or mishandling a specific request type.
- Detail
- Per-method results include HTTP status code, response time, and best-effort DNS / connect / TLS / first-byte phase timings when the Node HTTP client exposes them.
- Cadence
- Every 5 minutes, in parallel across 4 independent probe methods (HTTP/1.1 with strict TLS, HTTP/2, a browser User-Agent GET, and a curl-style HEAD) from our edge network. We check probe diversity, not geography — if a site blocks a non-browser User-Agent or only speaks HTTP/1.1, the four cards show it.
- Rate-limited targets
- If a host returns 429 or consistently drops connections from our IPs, we cap retries at 3 and report the last observed status, we do not flood the target to confirm the outage.
- Data source
- Our verdict is based on direct multi-method probes, every result above is a live network request, never a Twitter mention or DownDetector aggregate. User reports, when shown, appear separately below as a supplementary signal and are never used to determine the up/down verdict.