duga.jp
Mixed
Results vary across duga.jp: of 3 URLs tested, 2 are blocked and 1 is disrupted some of the time. The Great Firewall silently drops its packets so requests time out and resets the connection. 87 tests have been run under this domain since 2012-05-11, the most recent on 2026-06-18.
The two are filtered by different means — an unencrypted request by the address and keywords it carries in the clear, an encrypted one by the server name in its TLS handshake — so one working while the other does not is normal.
The site itself
http://duga.jpas of 2026Blockedhttps://duga.jpIntermittentPages and subdomains (1)
http://cd5.duga.jpas of 2026BlockedAbout duga.jp and the Great Firewall
Results vary across duga.jp: of 3 URLs tested, 2 are blocked and 1 is disrupted some of the time. The Great Firewall silently drops its packets so requests time out and resets the connection. 87 tests have been run under this domain since 2012-05-11, the most recent on 2026-06-18.
Plain HTTP and HTTPS differ here: http://duga.jp is blocked, https://duga.jp is intermittent. The two are filtered by different means — an unencrypted request by the address and keywords it carries in the clear, an encrypted one by the server name in its TLS handshake — so one working while the other does not is normal.
A VPN or another circumvention tool routes the request outside mainland China, past the filtering that blocks duga.jp. GreatFire runs GreatFire VPN; the Analyzer also tests the domains of many VPN and proxy providers, so you can check whether one is reachable before relying on it.
Elsewhere on the site
Each URL's status is its verdict over the last 90 days, the same one its own page headlines.