From home I cannot connect to the following sites (either partially or completely): abritel.fr, homeaway.fr, airbnb.com.
From the SAME computers, if I try from 3G, from work or from my neighbor's, it works.
The computers are 2 linux laptops, one linux server and one Android phone.
I can ping the sites, traceroute is identical (except for the first hop, my neighbor is with the same internet provider). But wget/links/firefox does a timeout in http or https "HTTP request sent, awaiting response".
I've changed DNS without success. I don't know what I can try next.
Hundreds of other websites do work fine but what is really really strange is that those that don't work are related to renting.
My house connection is an ADSL modem, there's no antispam on it and only an inbound firewall. I've reset it twice and checked its settings. Problem is the same if I connect to it in wifi or cat5.
I've contacted my provider who hasn't been any help so far and I don't know how to diagnose this better.