Singapore's InfoComm Development Authority has deployed wifi with the branding Wireless@SG across the public areas (changi airport, libraries, etc.) using Antlabs SSG to proxy users to their "home" networks. While the service has no cost, one still needs to register for free with icell network's wifi service with an SMS-enabled cellphone with an SG phone-number, after December 2009 it seems that users will have to pay for access through one of the carriers.
From the MAC OUI (00:10:f3) of both the SSG and wireless AP, it seems that Antlabs uses nexcom's embedded products and probably runs their own distro of linux or bsd on it; nmap gives the following probabilities:
The setup occasionally will not reply to DHCP or DNS requests (only a slight problem ;), even though the proxy and wireless components seem live (you can tcpdump and see other people's traffic working). One quick workaround is to assign yourself an IP in the available range, so sniff to see what they use (the National Library uses 10.128.0.0/16 gw 10.128.255.254/00:10:f3:07:13:32). When the DNS server dies, you need the following /etc/hosts entries:
192.168.0.2 ezxcess.antlabs.com 18.104.22.168 login.icellwireless.netNote that the 192.168.0.2 seems standardized, however it may vary, so you may have to nmap -sP -n 192.168.0.0/24 to find out which IP the SSG uses.