Ở đây chúng ta thấy các máy chủ tên (hư cấu) (hư cấu) miền nghiêm túc việc cung cấp tất cả các thông tin địa chỉ đã có sẵn. Đây không phải là to lớn tìm thấy, nhưng nó không cho chúng tôi biết địa chỉ IP cho các máy chủ web, cũng như trao đổi mail (MX) . | 6 Part I Hacking Fundamentals Here we see the fictitious nameserver for fictitious domain dutifully delivering all the address information it has available. This isn t a tremendous find but it does tell us the IP address for the web server http as well as the mail exchanger MX . We can also tell that the mail server and the web server are on two separate networks. Zone transfer attempts will succeed only against a name server that is considered to be authoritative for the domain that you want to list. We don t need another tool to find the authoritative server nslookup continues to be our one-stop shop set type any Server Address Non-authoritative answer MX preference 30 mail exchanger primary name server responsible mail addr serial 2003032521 refresh 10800 3 hours retry 3600 1 hour expire 604800 7 days default TTL 300 5 mins Internet address nameserver nameserver Internet address If you re more comfortable with GUI-based tools Sam Spade for Windows http ssw is a powerful footprinting tool with an emphasis on spam tracing. Zone transfers are disabled by default but can be activated by toggling an option under Edit I Options I Advanced. Once enabled zone transfers are simply a matter of supplying the domain name and the authoritative server as shown in Figure 1-1. Sam Spade also has a dig function that will return the authoritative nameserver for whatever domain name you specify one-click footprinting. Restrict Zone Transfers The simplest way to prevent attackers from obtaining zone transfer data from your servers is to block TCP 53 at your firewall or border router. Normal DNS lookups are conducted over UDP so it is not .
