I think so. It's enough to deal with the current censorship with all kinds
of DNS injection. If there's any problems in the future, then we can fix it
later.
在 2012-9-23 上午12:14，"Zubair Nabi" <zn.zubairn...@gmail.com>写道：
> Thanks. But do you think this is the best mechanism to catch such sort of
> censorship?
>
> On Sat, Sep 22, 2012 at 8:23 PM, Zhongjie Wang <wzj...@gmail.com> wrote:
>
>> Nice work ;) I've learnt something new, I used to think only A records
>> can be retrieved.
>>
>>
>> On Sat, Sep 22, 2012 at 8:33 PM, Zubair Nabi <zn.zubairn...@gmail.com>wrote:
>>
>>> There are various libraries available for every language which allow you
>>> to fetch the DNS record based on the hostname. For the Android agent I'm
>>> using DNSJava (http://www.xbill.org/dnsjava/). Sample code from the
>>> Android agent:
>>>
>>> https://github.com/umitproject/openmonitor-android-agent/blob/master/icm-mobile/src/org/umit/icm/mobile/connectivity/DNSLookup.java
>>>
>>> and how it is used for each website URL:
>>> Go to method setupDNSRecords()
>>> *
>>> https://github.com/umitproject/openmonitor-android-agent/blob/master/icm-mobile/src/org/umit/icm/mobile/connectivity/WebsiteDetails.java
>>> *
>>>
>>>
>>> On Sat, Sep 22, 2012 at 5:25 PM, Zhongjie Wang <wzj...@gmail.com> wrote:
>>>
>>>> Yes, I understand. But how do retrieve its DNS record?
>>>> 在 2012-9-22 下午5:17，"Zubair Nabi" <zn.zubairn...@gmail.com>写道：
>>>>
>>>> Hi Alan,
>>>>>
>>>>> Currently, we just open the website through its hostname and check its
>>>>> status code. What I propose is that we retrieve its A DNS record as well
>>>>> which would would give us the IP addresses for that domain name. That
>>>>> information along with the NS and SOA records can be used by the
>>>>> aggregator
>>>>> to check whether we accessed the actual website or were we redirected to a
>>>>> default page. The reason the agents do this themselves is that they only
>>>>> have access to local information.
>>>>>
>>>>> On Fri, Sep 21, 2012 at 6:57 PM, Zhongjie Wang <wzj...@gmail.com>wrote:
>>>>>
>>>>>> Hi Zubair,
>>>>>> Yeah, actually I've known the things you mentioned. For some
>>>>>> ISPs in China, if their DNS servers couldn't resolve a DNS request, it
>>>>>> will
>>>>>> return a default "error" page, which IP address is owned by the ISP. I
>>>>>> don't know whether this could be called a DNS injection. But it's a good
>>>>>> habit to examine the IP address for each website. How do you handle a
>>>>>> website with multiple IP addresses like google.com?
>>>>>>
>>>>>> Cheers,
>>>>>> Alan
>>>>>>
>>>>>> On Thu, Sep 20, 2012 at 9:28 PM, Zubair Nabi <zn.zubairn...@gmail.com
>>>>>> > wrote:
>>>>>>
>>>>>>> Guys,
>>>>>>>
>>>>>>> I just realised that some censoring entities such as the GFW of
>>>>>>> China use DNS injection to censor websites. Currently, we decide
>>>>>>> whether a
>>>>>>> website is blocked or not by analysing its HTTP status code (i.e. if its
>>>>>>> 200 or not). This will not work in case of DNS injection, because the
>>>>>>> HTTP
>>>>>>> status code would be 200 even though we won't be able to access the
>>>>>>> actual
>>>>>>> website. Therefore, I propose performing DNS look up for each website
>>>>>>> and
>>>>>>> adding the A, SOA, and NS DNS records to the website report. On the
>>>>>>> basis
>>>>>>> on these, the aggregator can decide whether a website is blocked or not.
>>>>>>> You can read up on these records here:
>>>>>>> http://www.debianhelp.co.uk/dnsrecords.htm. I've already added this
>>>>>>> mechanism to the Android agent.
>>>>>>> Any objections or comments on this?
>>>>>>>
>>>>>>> --
>>>>>>> Best,
>>>>>>> Zubair
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> ------------------------------------------------------------------------------
>>>>>>> Everyone hates slow websites. So do we.
>>>>>>> Make your web apps faster with AppDynamics
>>>>>>> Download AppDynamics Lite for free today:
>>>>>>> http://ad.doubleclick.net/clk;258768047;13503038;j?
>>>>>>> http://info.appdynamics.com/FreeJavaPerformanceDownload.html
>>>>>>> _______________________________________________
>>>>>>> Umit-devel mailing list
>>>>>>> Umit-devel@lists.sourceforge.net
>>>>>>> https://lists.sourceforge.net/lists/listinfo/umit-devel
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> Zhongjie Wang
>>>>>> Master Candidate
>>>>>> Computer System Architecture
>>>>>> Peking University, China
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Best,
>>>>> Zubair
>>>>>
>>>>>
>>>
>>>
>>> --
>>> Best,
>>> Zubair
>>>
>>>
>>
>>
>> --
>> Zhongjie Wang
>> Master Candidate
>> Computer System Architecture
>> Peking University, China
>>
>
>
>
> --
> Best,
> Zubair
>
>
------------------------------------------------------------------------------
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Make your web apps faster with AppDynamics
Download AppDynamics Lite for free today:
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http://info.appdynamics.com/FreeJavaPerformanceDownload.html
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