On Tue, 2001-09-04 at 12:51, Alex Blewitt wrote:
> I use exim 3.12 (8 Jun 2001) and had an interesting problem with
> netmasks recently; to prevent relaying, I had configured a netmask of:
>
> 194.203.158.80/4
This means that you are allowing IPs in the range 192.0.0.0 -
207.255.255.255 to relay
> However, it was letting some domains use our site as a relay; for
> example
>
> 195.224.76.132
yep - thats in the range you specified.
> I have no idea why this is the case; perhaps it was treating '4' as the
> start of '48'? It was disallowing some IP addresses (such as
> 129.215.153.197).
The /4 means that the netmask you are using has 4 one bits at the start
- ie 240.0.0.0
> Is this user error? The documentation doesn't say that it has to be any
> multiple of '8'.
I think you need to read up on what CIDR netmask widths actually mean
Nigel.
