Location
United States
Country level only
Domain
penguin-mail.com
Served through Cloudflare's network, which answers from the location nearest each visitor.
Still looking this up. This tab fills in as the answers arrive.
Network Every network on the internet has an autonomous system number (ASN). This is the one that announces this address.
AS13335Cloudflare
Cloudflare, Inc.
BGP prefixPrefix The block of addresses this IP is announced in to the rest of the internet. RPKI valid means the block's owner signed off on the network announcing it.
RPKI valid172.67.176.0/20
Seen by 3,395 peers
Latency Round trip for an HTTPS request from your browser to the site and back, including the server's reply time.
Live— ms
Measuring from your browser…
At a glance
Route
Finding a probe near you…
Networks crossed
Each network is an autonomous system (AS). Your traffic is handed from one to the next where they connect, following
the routes BGP advertises.
- AS16509Anthropic, PBC
- AS13335Cloudflare
Tracing from a probe near you with Globalping. Hop locations that its round-trip times rule out are left off the map.
DNS records
TypeNameValueTTL
Apenguin-mail.com172.67.180.2465 min
Apenguin-mail.com104.21.31.2425 min
AAAApenguin-mail.com2606:4700:3035::ac43:b4f65 min
AAAApenguin-mail.com2606:4700:3033::6815:1ff25 min
NSpenguin-mail.comcoby.ns.cloudflare.com1 day
NSpenguin-mail.comines.ns.cloudflare.com1 day
MXpenguin-mail.com1 aspmx.l.google.com1 hr
MXpenguin-mail.com10 alt3.aspmx.l.google.com1 hr
MXpenguin-mail.com10 alt4.aspmx.l.google.com1 hr
MXpenguin-mail.com5 alt1.aspmx.l.google.com1 hr
MXpenguin-mail.com5 alt2.aspmx.l.google.com1 hr
TXTpenguin-mail.com"google-site-verification=v8OC0zFFXna6x6ZfZMEZ31BPP3uE18req1XMXbZ6e9I"1 hr
TXTpenguin-mail.com"v=spf1 include:_spf.google.com ~all"1 hr
HTTPSpenguin-mail.com1 . alpn=h3,h2 ipv4hint=104.21.31.242,172.67.180.246 ech=AEX+DQBBuQAgACBJd9yXs07dlRnZ68LhTwNCPlph9bOtO6ibiePn44zcaAAEAAEAAQASY2xvdWRmbGFyZS1lY2guY29tAAA= ipv6hint=2606:4700:3033::6815:1ff2,2606:4700:3035::ac43:b4f65 min
Partly protected
There's no DMARC policy, so each receiver decides for itself what to do with mail that fails penguin-mail.com's SPF check.
- Receives mail
- Google Workspace
- Mail servers
- aspmx.l.google.comalt1.aspmx.l.google.comalt2.aspmx.l.google.com+2 more
- SPFLists the servers allowed to send mail for the domain. Receivers check it against the sending server.
- Soft-fails everything else1 of 10 DNS lookups · includes _spf.google.com
- DMARCTells receivers what to do with mail that fails SPF and DKIM: nothing (none), spam folder (quarantine) or reject.
- Missing
- MTA-STSRequires other mail servers to use encrypted connections (TLS) when delivering to this domain.
- Not published
- TLS reportsAsks other mail servers to report failed encrypted deliveries (TLS-RPT).
- Not requested
- BIMIA brand logo that some mail apps show next to authenticated mail from the domain.
- Not published
HTTPS
Certificate
Valid- Issuer
- Sectigo
- Issuing CA
- Sectigo Public Server Authentication CA DV E36
- Covers
- *.penguin-mail.com, penguin-mail.com
- Also validOther unexpired certificates for this name, found in Certificate Transparency logs.
- 12 more certificates
Oct 1, 202679 days leftDec 29, 2026
From Certificate Transparency logs, via Cert Spotter.
Security
A+- HSTSStrict-Transport-Security makes browsers refuse plain HTTP to this site. Preloaded sites are HTTPS-only even on a first visit.
- 1 year
- HTTP → HTTPSWhether the plain http:// address redirects visitors to the secure one.
- Doesn't redirect
- HTTP/3The newest HTTP, over QUIC. Announced in the alt-svc header or the domain's HTTPS DNS record.
- Available
- Encrypted helloEncrypted Client Hello (ECH) hides which site you're visiting from anyone watching the connection.
- Supported
- CAADNS records naming the only certificate authorities allowed to issue certificates for the domain.
- Any CA may issue
- security.txtA standard file (RFC 9116) telling security researchers how to report vulnerabilities.
- support@penguin-mail.com
Security headers 7 of 7
- HSTSpresent
- CSPpresent
- Framingpresent
- No sniffingpresent
- Referrerpresent
- Permissionspresent
- Isolationpresent
Response
200 OK329 ms from CMH · 24.9 KBDNS lookup35 ms
200 penguin-mail.com329 ms
DNSConnect (TCP + TLS)Waiting for the replyFrom Cloudflare's CMH data center
Website
Page
Penguin Mail: mail and calendar for Linux and macOS
Gmail, Microsoft and any IMAP or POP3 account, with your calendar and contacts, in one fast app on your own computer.
- Language
- English
- Theme color
- #fbf7f0
Built with
- CloudFrom the provider's published address ranges.
- Cloudflare
- CDN
- Cloudflarecf-ray header
- Framework
- Nuxtx-powered-by header
Tech stack
Built with Each entry says what gave it away: a response header, a cookie's name, an asset's path or file name, or markup the tool leaves in the page. Versions are checked against endoflife.date's support schedules and, for JavaScript packages, OSV's vulnerability database, which carries GitHub's security advisories.
CDN & edge
- Cloudflare
cf-ray header
Framework
- Nuxt
x-powered-by header
UI
- Vue
Nuxt renders with Vue
Styling
- Tailwind CSS
46 Tailwind CSS class names
Fonts
- Manrope
self-hosted font
How it's made
- RenderingPrerendered pages are built ahead of time and served as files. Pages rendered on each request are built by server code for every visitor. Pages drawn in the browser arrive nearly empty and depend on JavaScript, which most AI crawlers don't run. Islands are interactive parts in otherwise static HTML.
- Complete HTML735 words before any script runs
- HTML
- 24.9 KB
- Data for scriptsData the server writes into the HTML so JavaScript can pick up where the server left off (hydration). Browsers download and parse all of it before the page responds, so large payloads slow pages down, even when the page looks ready.
- Nuxt state 3.4 KB · 14% of the HTML
- Scripts
- 1 file · 3 inlineall from this site · 1 modules
Code from other sites Scripts a page loads from another domain run with the same power as its own code: they can read what visitors type and change the page. heade.rs checks what the HTML loads, not what tag managers add once they run.
The HTML loads no scripts from other sites.
Response headers
- cf-ray
- a497ca6509a3a691-CMH
- connection
- close
- content-length
- 25515
- content-security-policy
- default-src 'none'; script-src 'self' 'unsafe-inline' 'wasm-unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src 'self'; font-src 'self'; connect-src 'self'; base-uri 'none'; form-action 'none'; frame-ancestors 'none'
- content-type
- text/html;charset=utf-8
- cross-origin-opener-policy
- same-origin
- date
- Mon, 12 Oct 2026 17:23:07 GMT
- nel
- {"report_to":"cf-nel","success_fraction":0.0,"max_age":604800}
- permissions-policy
- camera=(), microphone=(), geolocation=(), interest-cohort=(), browsing-topics=()
- referrer-policy
- strict-origin-when-cross-origin
- report-to
{"group":"cf-nel","max_age":604800,"endpoints":[{"url":"https://a.nel.cloudflare.com/report/v4?s=Kidml1GvEa8aBbpHQk7ZiRvcTRMtlQ7vAtllGby0ObOmROuDqhwXPuM%2B%2F2XHJvFwQWlG%2FyiFBVAk1p1BViJLCu7NoejltZvyE%2BMd%2F%2BTtAASxnKq%2B1BjQ23roBbaY1MZxx… Show all
{"group":"cf-nel","max_age":604800,"endpoints":[{"url":"https://a.nel.cloudflare.com/report/v4?s=Kidml1GvEa8aBbpHQk7ZiRvcTRMtlQ7vAtllGby0ObOmROuDqhwXPuM%2B%2F2XHJvFwQWlG%2FyiFBVAk1p1BViJLCu7NoejltZvyE%2BMd%2F%2BTtAASxnKq%2B1BjQ23roBbaY1MZxxnDo9KJcE2rEJZZ2ZW6H"}]}- server
- cloudflare
- strict-transport-security
- max-age=31536000
- x-content-type-options
- nosniff
- x-powered-by
- Nuxt
- x-robots-tag
- index, follow, max-image-preview:large, max-snippet:-1, max-video-preview:-1
Details
Network
- IPv4
- 172.67.180.246
- ASNThe autonomous system number of the network that announces this address.
- AS13335
- Operator
- Cloudflare, Inc.
- CDNFrom the provider's own published list of its address ranges.
- Cloudflare
- PrefixThe block of addresses announced over BGP that contains this address.
- 172.67.176.0/20
- RPKIWhether a signed record (ROA) authorizes this network to announce this prefix.
- Valid
- VisibilityHow many bgp.tools peers carry this announcement.
- 3,395 peers
- Type
- Content
- Registry
- ARIN
Location
Country level- Country
- United States
- Continent
- North America
Registration
RDAP- Registrar
- NameCheap, Inc.
- Registered
- Sep 25, 202617 days ago
- Expires
- Sep 25, 2028next year
- Updated
- Sep 25, 2026
- StatusRegistry flags on the domain, such as locks that stop unauthorized transfers or changes.
- Transfer locked
- DNSSECDNSSEC signs DNS answers so they can't be forged on the way to you.
- Unsigned
- Name servers
- coby.ns.cloudflare.comines.ns.cloudflare.com
- Registrant
- Redacted for privacy
Sep 25, 2026714 days leftSep 25, 2028
AI & agents
Open to AI search, closed to training
The crawlers behind AI search may come in, and robots.txt turns away GPTBot, ClaudeBot, Google-Extended and 6 more. Blocking Google-Extended also keeps it out of Gemini's answers.
Crawlers
Blocks 15 of 25TrainingSearchOn request
They visit a page when someone asks an assistant about it. ChatGPT's, Perplexity's, Meta's and Amazon's treat robots.txt as advisory;
Anthropic's and Mistral's follow it.
OpenAIGPTBotblockedOAI-SearchBotallowedChatGPT-Userblocked
AnthropicClaudeBotblockedClaude-SearchBotallowedClaude-Userblocked
GoogleGoogle-ExtendedblockedGooglebotallowed—
Microsoft—bingbotallowed—
AppleApplebot-ExtendedblockedApplebotallowed—
Perplexity—PerplexityBotallowedPerplexity-Userblocked
MetaMeta-ExternalAgentblockedMeta-WebIndexerallowedMeta-ExternalFetcherblocked
AmazonAmazonbotblockedAmzn-SearchBotallowedAmzn-Userblocked
MistralMistralAI-TrainingblockedMistralAI-IndexallowedMistralAI-Userblocked
OthersCCBotblockedBytespiderblockedDuckAssistBotallowed
- Can cite itThe AI products that can use the site in their answers: each answers from one crawler (OAI-SearchBot for ChatGPT search, Googlebot for AI Overviews, bingbot for Copilot), and robots directives on the front page, like noindex, nosnippet and noarchive, keep some out.
- ChatGPT searchClaudePerplexityAI OverviewsCopilotMeta AISiri
- Kept out of
- Gemini: robots.txt blocks Google-Extended
Content signals
Lines in robots.txt (Cloudflare's Content Signals Policy) saying whether pages may be used for search, as input to AI answers (ai-input) and for AI
training. No major AI company has said it follows them.
search=yesai-train=nouse=reference
Cloudflare writes part of this robots.txt, and can also block AI crawlers at its edge whatever the file says.
Reading
- Without JavaScriptText on the front page before any scripts run: what GPTBot, ClaudeBot, PerplexityBot and most agents read. Google, Bing and Apple's crawlers run scripts.
- 735 words
- MarkdownAgents like Claude Code, Cursor and OpenCode ask for Markdown in their Accept header. It's the page without its markup, so it costs them far fewer tokens.
- Not offered
- llms.txtA Markdown file listing a site's key pages for AI tools. Coding agents read it; search crawlers mostly don't.
- 7 links in 3 sections
- Structured dataschema.org JSON-LD in the page: facts about the site in a form machines read directly.
- WebSite, WebPage, Organization, SoftwareApplication
Tools Ways an AI agent can do things on the site, not just read it: an MCP server that apps like Claude, ChatGPT and Cursor connect to, an API catalog, packaged agent skills, a shopping profile (UCP), or tools the page offers AI in the browser (WebMCP). heade.rs looks in the official MCP Registry and the files the site publishes under /.well-known/.
No MCP server, API catalog, agent skills, shopping profile or in-page tools found.