[bdNOG] Can't access a website using dual stack

Sun Feb 5 22:55:19 BDT 2017

Dear Brian,

Thank you for explaining. I appreciate it.

I'm trying to connect them, let's see how it goes.

Best regards,

Awal

On 2/5/17 7:36 PM, Brian Candler wrote:
> On 05/02/2017 12:49, Md. Abdul Awal wrote:
>> Those who are using dual stack, would you please check if you can browse
>> Malaysian High Commission's page
>> http://www.kln.gov.my/web/bgd_dhaka/home ?
>>
>> When I use IPv4 only, it works fine. When I use IPv6 only I can't browse
>> the page, but it seems the website is IPv6 enabled.
>>
>> Surprisingly, if I use dual stack, I can't browse the page which is the
>> main problem I'm facing. I can't figure out whether the problem is in my
>> network or at their end. I'd really appreciate if somebody help me
>> through this?
> The problem is with their site.
>
> If it simply failed to connect on IPv6, a dual-stack browser would
> fall back to IPv4.
>
> However, what's actually happening is that it's accepting the
> connection on IPv6, but then hanging and not returning any content. In
> this situation, a dual-stack browser thinks the connection was
> successful so will not fall back.
>
> $ curl -v http://www.kln.gov.my/web/bgd_dhaka/home
> * About to connect() to www.kln.gov.my port 80 (#0)
> *   Trying 2400:7400:51:7d::20... connected
> > GET /web/bgd_dhaka/home HTTP/1.1
> > User-Agent: curl/7.22.0 (x86_64-pc-linux-gnu) libcurl/7.22.0
> OpenSSL/1.0.1 zlib/1.2.3.4 libidn/1.23 librtmp/2.3
> > Host: www.kln.gov.my
> > Accept: */*
> >
> <<< hangs here >>>
>
> Whereas if I force the connection on IPv4, it returns content:
>
> $ curl -4 -v http://www.kln.gov.my/web/bgd_dhaka/home
> * About to connect() to www.kln.gov.my port 80 (#0)
> *   Trying 202.60.59.122... connected
> > GET /web/bgd_dhaka/home HTTP/1.1
> > User-Agent: curl/7.22.0 (x86_64-pc-linux-gnu) libcurl/7.22.0
> OpenSSL/1.0.1 zlib/1.2.3.4 libidn/1.23 librtmp/2.3
> > Host: www.kln.gov.my
> > Accept: */*
> >
> < HTTP/1.1 200 OK
> < Set-Cookie: JSESSIONID=202EBBC7FD0F7144C5FA2A78B9DF4A58; Path=/
> < Liferay-Portal: Liferay Portal Standard Edition 5.2.3 (Augustine /
> Build 5203 / May 20, 2009)
> < Content-Type: text/html;charset=UTF-8
> < Content-Length: 110759
> < Date: Sun, 05 Feb 2017 13:33:30 GMT
> < Server: wisma
> <
> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
> "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
> <html dir="ltr" xmlns="http://www.w3.org/1999/xhtml">
> <head>    <title>Portal - Home</title>
> ... etc
>
> So you should get in touch with them. Either they should fix the
> serving of content over IPv6, or they should remove the AAAA record
> from the DNS.
>
> Regards,
>
> Brian.

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