| Configuration
files: The
/etc/resolv.conf Ok. After reading the /etc/hosts page, we know know now to define the host names of our computers in the network. The manual hostname configuration is superb for small networks (a LAN of 10-20) computers, but what if: connecting to the Internet or using portable conputers in our LAN? The Internet is a difficult case considering the amount of computers that are constantly communicating. A LAN or WAN with detachable computers (think laptops that you connect to the LAN and then take away with you) always connecting with dynamic IP is also a difficult case. Q: Why dynamic IP? A: In big networks (such as the Internet) choosing dynamic IP is preferred over static for practical reasons - try to setup a B Class network with 64.000 computers by remembering their static IP adresses. Now think of them constantly appearing to - disappearing from the network! Then try to connect to each one remembering their IP adresses EVEN if they are static. Remembering www.apple.com is much more practical than 17.112.152.32 (present IP). Now think what would happen if this IP adress changed frequently. A little History: The times that Internet was rather "small" (and not known as "Internet" yet), there used to be big lists (10000+) of manual hostname resolving that were frequently updating /etc/hosts (or something relevant, considering non-Unix OSes). To solve the vast growth that would make the manual configuration plain impossible, a dynamic mechanism was created: The Host Name Resolving. Name Servers that perform synchronization between them very often, are always online to resolve our hostname queries. Nowdays: So, to connect to www.apple.com now, we ask a Name Server, or DNS (Domain Name Server) for a more "internet" oriented definition, which in it's turn consults its database, resolves the hostname and returns the IP adress : 17.112.152.32 Even if for the average user's OS this operation is transparent, it actually takes place. Upon connecting to the Internet we obtain the IP adress of one or two DNS Servers. For educational and practical reasons I have decided to do this operation manually. Manual or not, in Unix-like OSes, the Name Server information is stored in /etc/resolv.conf. If you encounter problems connecting to the Internet, or to your LAN or WAN, contact the appropriate administrator and obtain the DNS (or Name Server) addresses. I did that and obtained the (hypothetical in this page) adresses of a.b.c.d and w.x.y.z So, my hypothetical /etc/resolv.conf file is: search hol.gr nameserver a.b.c.d nameserver w.x.y.z |