I'm having some weird problems with ipv6 on my box. My ISP is set up for ipv6, my router and server both seem to have valid ipv6 addresses, and ipv6 connectivity seems to (nominally) be working: [darose@darsys12 ~]$ ping ipv6.google.com PING ipv6.google.com(lga25s63-in-x0e.1e100.net (2607:f8b0:4006:81b::200e)) 56 data bytes 64 bytes from lga25s63-in-x0e.1e100.net (2607:f8b0:4006:81b::200e): icmp_seq=1 ttl=55 time=13.1 ms 64 bytes from lga25s63-in-x0e.1e100.net (2607:f8b0:4006:81b::200e): icmp_seq=2 ttl=55 time=11.0 ms ^C [darose@darsys12 ~]$ curl -I ipv6.google.com HTTP/1.1 200 OK Date: Mon, 23 Jul 2018 15:35:06 GMT Expires: -1 Cache-Control: private, max-age=0 Content-Type: text/html; charset=ISO-8859-1 P3P: CP="This is not a P3P policy! See g.co/p3phelp for more info." Server: gws X-XSS-Protection: 1; mode=block X-Frame-Options: SAMEORIGIN Set-Cookie: 1P_JAR=2018-07-23-15; expires=Wed, 22-Aug-2018 15:35:06 GMT; path=/; domain=.google.com Set-Cookie: NID=135=SV0kZxYO7fTnUYm0ZJFnRx-d17kNOyTyHgPzv-xKmj_Q-LXYz_LuiBsAGHesREIbtwbKZAKYeqU8fh0saXfnylDGsBbAwCQDAKeG9iT9PwmBc0IBntqO0xkklns-YThY; expires=Tue, 22-Jan-2019 15:35:06 GMT; path=/; domain=.google.com; HttpOnly Transfer-Encoding: chunked Accept-Ranges: none Vary: Accept-Encoding However, certain server utilities - most notably freshclam (clamav) and the w3m command line web browser - are having problems successfully making connections using ipv6. For example: w3m via ipv4 works: [darose@darsys12 ~]$ w3m -4 -dump google.com | grep -i google Google [Google Search][I'm Feeling Lucky] tools Advertising ProgramsBusiness Solutions+GoogleAbout Google but w3m via ipv6 doesn't: [darose@darsys12 ~]$ w3m -6 -dump ipv6.google.com ... hangs forever ... Even weirder: this works: [darose@darsys12 ~]$ w3m -4 -dump_head google.com HTTP/1.0 200 OK Date: Mon, 23 Jul 2018 15:21:52 GMT Expires: -1 Cache-Control: private, max-age=0 Content-Type: text/html; charset=ISO-8859-1 Content-Encoding: gzip Server: gws Content-Length: 4675 X-XSS-Protection: 1; mode=block X-Frame-Options: SAMEORIGIN Set-Cookie: 1P_JAR=2018-07-23-15; expires=Wed, 22-Aug-2018 15:21:52 GMT; path=/; domain=.google.com ... but this doesn't: [darose@darsys12 ~]$ w3m -6 -dump_head ipv6.google.com ... hangs ... until I hit control C ... then succeeds after the control-c (wtf?!?!?) ^CHTTP/1.0 200 OK Date: Mon, 23 Jul 2018 15:39:44 GMT Expires: -1 Cache-Control: private, max-age=0 Content-Type: text/html; charset=ISO-8859-1 Content-Encoding: gzip Server: gws Content-Length: 4680 X-XSS-Protection: 1; mode=block X-Frame-Options: SAMEORIGIN Set-Cookie: 1P_JAR=2018-07-23-15; expires=Wed, 22-Aug-2018 15:39:44 GMT; path=/; domain=.google.com And freshclam fails as well: [darose@darsys12 ~]$ sudo freshclam ClamAV update process started at Mon Jul 23 11:41:13 2018 WARNING: Your ClamAV installation is OUTDATED! WARNING: Local version: 0.100.0 Recommended version: 0.100.1 DON'T PANIC! Read https://www.clamav.net/documents/upgrading-clamav main.cld is up to date (version: 58, sigs: 4566249, f-level: 60, builder: sigmgr) nonblock_recv: recv timing out (30 secs) WARNING: getfile: Download interrupted: Operation now in progress (IP: 2400:cb00:2048:1::6810:bb8a) WARNING: getpatch: Can't download daily-24740.cdiff from database.clamav.net Trying host database.clamav.net (2400:cb00:2048:1::6810:b98a)... nonblock_recv: recv timing out (30 secs) WARNING: getfile: Download interrupted: Operation now in progress (IP: 2400:cb00:2048:1::6810:b98a) WARNING: getpatch: Can't download daily-24740.cdiff from database.clamav.net Downloading daily-24740.cdiff [100%] ... I'm really stumped as to how ipv6 could partially fail like this only on specific apps. Seems like it should either completely work or completely fail. Anyone have any idea what might be happening here and/or how to fix? Thanks, DR