There, I fixed the hotel wifi
Hanoi, 5 years ago, I think they hotel was Blue Lotus or something like that: I could connect to the hotel wifi with the phone but there was no Internet access. Bummer, because I needed it to find out what to do in the city (What, talk to someone?! In person? Pfft.) Well, I put the gateway IP in browser...nice, a router login page! Tried the usual default admin passwords and voilà, I'm in. Looked through the configuration, couldn't see anything wrong so I just selected the reboot option, waited for a minute... and Internet! Yay!
Turns out the tourist guides are not worth anything. Just go to the street side stalls with the small plastic chairs, you get the best food there!