Vodacom prevents certain HTTP content

[glamprecht]

We found that a computer with a Vodacom SIM card cannnot access certain services from certain websites, whereas putting a MTN sim card in the same computer, it was able to access those services.

All traffic relate to port 80.

It appears that some Ajax functions do not work on Vodacom, but works on MTN.

Is there a workaround for this on Vodacom, because it is very frustrating for us who has spend hundreds of thousands on very complex ERP/RTU server software, only MTN customers can use all the functions because Vodacom block certain HTTP traffic.

 

[ozziej]

You sure they deliberately blocking it and it's not a DNS or routing issue. Ask them. I seriously doubt they are blocking anything especially over http.

 

[glamprecht]

I am quite sure that it is not DNS or routing issue since I am able to access all the pages on the site. I am also sure the JS is not using anything except HTTP and not using any port except 80. We are looking now with wireshark what is being blocked or why it is not working. The principle still stands that I have a website that works with a MTN sim card, but does not work with a Vodacom SIM card. This means that whenever in future I visit a site on my cellphone/laptop both currently with Vodacom SIM cards, and have difficulty, I will always suspect Vodacom. Filtering HTTP traffic is serious since nobody is expecting it.

 

[ODTech]

I am quite sure that it is not DNS or routing issue since I am able to access all the pages on the site. I am also sure the JS is not using anything except HTTP and not using any port except 80. We are looking now with wireshark what is being blocked or why it is not working. The principle still stands that I have a website that works with a MTN sim card, but does not work with a Vodacom SIM card. This means that whenever in future I visit a site on my cellphone/laptop both currently with Vodacom SIM cards, and have difficulty, I will always suspect Vodacom. Filtering HTTP traffic is serious since nobody is expecting it.

Have you tried using another DNS just to troubleshoot?
Google DNS is pretty stable and have worked with anything i tried it with.
8.8.8.8
8.8.4.4

I can't access one of my suppliers websites unless i use the google dns settings. I use a Webafrica capped home package.

 

[MrGray]

In the past Vodacom was found to be injecting js into the responses, as well as altering image quality. I think after a fuss was kicked up about that they stopped it but if it was possible before it can happen again. You'd need to compare what you're getting back on the client side with Fiddler or something from both a MTN and Vodacom connected client as well as what headers the server side is getting.

 

[sajunky]

You'd need to compare what you're getting back on the client side with Fiddler or something from both a MTN and Vodacom connected client as well as what headers the server side is getting.

^This.
I made such comparison against Telkom and found that Vodacom traffic goes through numerous 3rd-party proxy servers. These sites do data mining of Vodacom customers. It is additional source of revenue. It also affects downloads. It seems to be not intentional, but when proxy server goes corrupt, it works the same as a blocked content.
See: http://mybroadband.co.za/vb/showthread.php/704190-Can-Vodacom-fix-their-transparent-proxies?

 

[glamprecht]

OK we found the problem. Some CR/LF in our javascript is going missing, resulting in some code becoming comments and the JS failing on the client side. It is interesting that our JS is sent through Gzipped. This means that Vodacom unzip the files to check for malicious content and then zip it again. Somewhere in that process Vodacom's proxy has a bug modifying the content.

It is quite a serious matter for corporates who want to use Vodacom if they modify content. We can proof that it happens. A CR/LF in a legal document can lead to serious mistakes. The whole idea of using TCP/IP is that content is checked through a checksum, to guarantee that what is received is the same than what was transmitted. The Vodacom server software architecture is seriously flawed if it allows content to be modified. Rather block it, but dont change it.