Re: question about net address
On Sun, 19 Mar 2023 18:28:40 +0800
coreyh@free.fr wrote:
> On 19/03/2023 18:00, David Christensen wrote:
> > On 3/18/23 16:31, coreyh@free.fr wrote:
> >> On 19/03/2023 06:17, Kushal Kumaran wrote:
> >>> On Sat, Mar 18 2023 at 07:28:23 PM, coreyh@free.fr wrote:
> >>>> Hello
> >>>>
> >>>> I know 192.168.1.0/24 is a valid C range for network address.
> >>>>
> >>>> but what does 192.168.1.1/24 mean?
> >>>>
> >>>> I ask this just for a setting in the SPF:
> >>>>
> >>>> spf.pinoad.se. 300 IN TXT "v=spf1
> >>>> ip4:188.66.63.1/24 -all"
> >>>>
> >>>
> >>> It means the same thing. 192.168.1.1/24 is the same range as
> >>> 192.168.1.0/24, but written by someone not paying too much
> >>> attention.
> >>
> >>
> >> That's correct. Thanks.
> >
> >
> > AIUI:
> >
> > * 192.168.1.0/24 identifies an IPv4 network with an address of
> > 192.168.1.0 and a network prefix of 24 bits. The address is within
> > the reserved private block 192.168.0.0/16. The prefix corresponds
> > to a class C network.
> >
> > * 192.168.1.1/24 identifies an IPv4 network interface with an
> > address of 192.168.1.1 and a network prefix of 24. The interface is
> > configured to communicate over the 192.168.1.0/24 network.
> >
> >
> >
>
> So for Inleed (a local ISP)'s SPF:
>
> spf.pinoad.se. 300 IN TXT "v=spf1
> ip4:188.66.63.1/24 -all"
>
>
> They specify only 188.66.63.1 to send email?
>
> But as far as I know their mailserver is 188.66.63.2:
>
> mail.inleed.xyz. 300 IN A 188.66.63.2
>
>
> Then this mail server should have problems in messages delivery.
>
>
Mail to/from a domain does not have to be sent by the same host as the
one which receives it. They may be the same computer, they may be
servers on different continents belonging to different companies.
Many businesses use a mail-cleaning service of some kind for received
mail, and many who receive mail directly send their outgoing mail
through their ISP or domain host.
--
Joe
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