It took me some time to find out that the http://pragprog.com page fails to load when a socks 5 proxy is active. Or maybe any kind of HTTP proxy. It could be interesting for the readers to know maybe. Don’t think this remark belongs to the errata stuff, so I post it here. This really is a specific problem but it could happen to others. In my case, the socks 5 proxying is done by SSH. So I have little room to experiment with sniffing.