Re: hangs/multiple servers

Tim Berners-Lee (
Thu, 19 Nov 92 18:29:03 +0100

> Date: Thu, 19 Nov 1992 09:38:35 +0000 (GMT)
> From: Kevin Hoadley <>

> The simple way to provide multiple servers would be to
> register the server name in the DNS with multiple A
> (address) records pointing to different machines. Then
> the clients could be mod'ed could try the second or third
> ... addresses if they couldn't get through to the first.

Ok, This seems a bery good idea, if that is the functionality which DNS
Let's try it.... Anyone care to mod HTTP.c? It's not obvious from
the gethostbyname that one is allowed to refer to different
struct hostent {
char *h_name; /* official name of host */
char **h_aliases; /* alias list */
int h_addrtype; /* host address type */
int h_length; /* length of address */
char **h_addr_list; /* list of addresses from name server */

That look like a list of aliases for one machine, rather than a
list of machines for one alias! But maybe the reverse will work.
So all machines support char **h_addr_list rather than the older
h_addr? We can probably differentiate using #ifdef h_addr
which is set to a macro if there IS a list. I assume you need then
separate entries for the virtual duplicate node and the actual
real nodes, so that you can speak to them sepately. Is this normal
and OK?

> How you keep info upto date accross multiple servers is
> a different matter, need some form of replication a la
> DNS zone transfers (or Quipu's extensions to X.500 ) ...
> Mind you, replication within www is a harder issue: a
> server might be sitting in front of datasets too large
> to sensibly duplicate.

> Kevin Hoadley, Rutherford Appleton Laboratory