[arch-general] ipv6 only half working

[David Rosenstrauch]

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 at 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 at 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 at 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 at darsys12 ~]$ w3m -6 -dump ipv6.google.com
... hangs forever ...



Even weirder:

this works:

[darose at 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 at 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 at 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