Global access to DH sites?


Hi all,

What kind of response do you get when you ping your site from or test your site’s availability at

I recently discovered that my site is blocked in China by checking here.

Which lead me to the above sites. I was quite frustrated to see 100% packet loss from

[]München, Germany
]Colone, Germany
[]New York, USA
]London, UK
[]Padova, Italy
]Moscow, Russia
[]Gdansk, Poland
]Athens, Greece
[*]and Budapest, Hungary

in addition to the expected Beijing and Shanghai, China. A test of shows that these test sites are working. Why are they not reaching DH???

And what can we do to avoid being banned in China? I assume its because one of my servermates is hosting a blog on one of the three Ts (Tibet, Tiananmen Square, and Taiwan).


I saw much the same list as you at

it will be interesting to see if andrewf has comment :wink:


For my own site, I got a similar set of failures on for a site of mine which had IPv6 enabled. Pinging the IPv4 address worked fine, so it’s possible this issue only affects IPv6 connectivity.

I’m not particularly familiar with our network infrastructure, though, so I couldn’t say what the issue is here.


Yeah, in the results, the IPv6 addresses lose packets more often than IPv4. Some report using the IPv6 address and getting a response though.

It’s frustrating because I’m using my site for my PhD research and trying to collect data from people around the world. If 20% are excluded (China), and then major population areas… well, it’s frustrating.

Any tips on getting unbanned in China? Can DH put all banned sites in a smaller IP pool so that other sites aren’t guilty by association?


i ran a check at just-ping using my IPv6 address and found that 50% of the test sites came back with 100% packet loss. shows that the site and server are both IPv6 compatible.

so it seems that IPv6 is not the problem…

I entered Google’s IPv6 address ( in just-ping and found packet loss from only two test sites, and both < 100%…

something’s up with DH?


Well, on a number of sites hosted on DH I got perfect response for sites with only IPv4, but for one site which also has an IPv6 address I got a similar picture as above. My findings are just as andrewf describes.


Interesting. Perhaps DH’s IPv6 is not yet fully fledged…

Maybe I’ll disable my IPv6 addresses for a while. I thought I was doing the right thing by helping the move away from IPv4, but it seems to still be buggy. All the IPv4 addresses have been allocated… I wonder when the great shift will finally happen?

On a positive note, I requested a server move, which just completed, and I’m delighted to find that my new IP has not (yet) been banned in China! So at least 20% of the world might be able to see my site now…


Actually i’m not sure what we know about where IPv6 is failing. Perhaps it’s the test site, or somewhere in-between…or it could as you point out, be a dreamhost IPv6 issue…


Possibly. I just used google’s ipv6 site as a baseline. i assume goggle’s got ipv6 sussed… but that’s just based on reputation. others have shown that just because it’s google, doesn’t necessarily mean it’s the best (their JS closure library, for example)


bobocat, that’s not as easy as one might think. The Chinese GFW (Great Firewall) generally blocks IP addresses, not individual sites, so it’s extremely difficult for us to identify what the exact sites responsible for blocks are.


China is one issue and it looks like you have solved that one or are on your way to solving…

On the other sites where it appears IPv6 may have a part in the puzzle, have you opened a support ticket for that? I don’t want to duplicate the effort, but the New York one concerns me the most…


No, LakeRat, I haven’t. Feel free and let us know how it goes. If IPv4 is working, then that’s fine for me now, but we all need to deal with IPv6 sooner rather than later.


I’m not sure i understand the conversion to IPv6 at this point. I think I’m just now understanding that IPv4 works from those locations, but what causes a users traffic to be routed one way or the other?

I too added IPv6 IPs to my domains after the newsletter mention, i wonder it’s better to delete them for now?


Briefly: IPv4 and IPv6 use separate addresses, and you publish both of them in DNS (using A and AAAA records, respectively). Machines which are IPv6-capable will look for both record types, and will use the v6 address if one is available.

If some of your domains are currently set up with IPv6 and you’re not using it — and particularly if you have no way to test it yourself! — it may be best to leave it off. There isn’t (yet!) any immediate advantage to having an IPv6 address added unless you, or a lot of your visitors, have v6 transit.

If you don’t know whether you have v6 transit, you can check at: (Spoiler: You probably don’t.)


Thank you. The brief explanation you have provided filled in many blanks for me.


Hi andrew, quite a few of us have noticed a lot of intermittant problems with IPv6 the last week. Is there a weird DH IPv6 outage or problem we need to be aware of? My business actually depends on having higher availability of IPv6 than of v4. There’s also nothing in the status site, and I had to put in a ticket which had fixed something. Any communications would be nice as to what happened and what issues may still be happening would be nice. Thanks in advance.