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
>>>>>>
>>>>>>
>>>>>>
>>>>>> ------------------------------------------------------------------------------
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>>>>>> Download AppDynamics Lite for free today:
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>>>>>> _______________________________________________
>>>>>> 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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