> On May 21, 2018, at 3:35 PM, Chris Adams <[email protected]> wrote: > > I ran into an odd issue with access to a website I manage from AT&T > mobile devices this weekend. The website worked for everybody not on > AT&T mobile, and AT&T mobile users could access other sites; the problem > was just this combination. > > Android and iOS phones, as well as a Linux system tethered to an Android > phone, all had the same problem. On the Linux system, I disabled IPv6 > in Firefox, and it could then connect. Browsers got various "connection > reset" type errors; on Linux, I could telnet to port 80 or 443, and it > would connect and immediately close. > > The site does have an IPv6 address, but I had missed getting the > webserver to listen on IPv6 (my mistake). Adding that looks to have > solved the problem. > > When I ran tcpdump on the server and had someone try to connect from > their AT&T mobile iPhone, I saw three connection attempts a few tenths > of a second apart (all refused by the server). > > My question is this: is AT&T mobile intercepting the TCP socket (and > not handling "connection refused" correctly)? Is that a known thing?
Yes they are. You can see this in test-ipv6.com it will report the proxy/Via Header addition. - jared
