On Jun 29, 2011 6:00 AM, "Ryan Malayter" <malay...@gmail.com> wrote: > > > > On Jun 28, 3:35 pm, Cameron Byrne <cb.li...@gmail.com> wrote: > > > > > AFAIK, Verizon and all the other 4 largest mobile networks in the USA > > have transparent TCP proxies in place. > > Do you have a reference for that information? Neither AT&T nor Sprint
No. > seem to have transparent *HTTP* proxies according to > http://www.lagado.com/tools/cache-test. I would have thought that > would be the first and most important optimization a mobile carrier > could make. I used to see "mobile-optimized" images and HTTP > compression for sites that weren't using it at the origin on Verizon's > 3G network a few years ago, so Verizon clearly had some form of HTTP > proxy in effect. > > Aside from that, how would one check for a transparent *TCP* proxy? By > looking at IP or TCP option fingerprints at the receiver? Or comparing > TCP ACK RTT versus ICMP ping RTT? > I am not familiar with that HTTP proxy test. As I said, they are likely using tcp proxies to get over tcp issues. I assume if you were sniffing both ends you could discover changes in parameters forced by the middle box. Cb
