Illegal DNS Domains Probably the most annoying and frustrating development in name services today has been the introduction of non-IANA sanctioned top level domains. These are present in Internet mail addresses of domain names ending with .biz, .med .nic and so on. While most of these are still tiny, if illegal domains begin to grow it will create an enormous headache for admins. Since these domain names are not listed in the major root nameservers, mail to them will bounce. If this fails, the mailserver's nameserver will have to be modified to include a special set of nameservers that list the illegal domain names.
Most sites have a policy against servicing illegal domain names.
Anti-Virus Software One area of concern when accepting inbound SMTP mail from the Internet is the transmission of virus programs. The Internet is connected to one card, and the internal network is connected to the other. The software scans all data traffic between the adapter cards, looking for virus patterns. This is a tarred, gzipped file. When expanded and untarred, it produces the uvscan executable.