[120465] in North American Network Operators' Group
Re: how it routes and network question
daemon@ATHENA.MIT.EDU (Truman Boyes)
Tue Dec 22 07:48:14 2009
From: Truman Boyes <truman@suspicious.org>
In-Reply-To: <40d8a95a0912220431p7232025bx338affded04c8bd0@mail.gmail.com>
Date: Tue, 22 Dec 2009 23:47:11 +1100
To: Deric Kwok <deric.kwok2000@gmail.com>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
Hi, your "hosting company" is likely NAT'ing or using load balancers on =
the front end. You are obviously not "reaching" those machines by =
ssh'ing into 192.168.x.x... Additionally, assuming that DHCP is handing =
out that address on the server that mask would likely not be all ones.=20=
Even Amazon EC2 instances use private addresses now on the backend ...=20=
Kind regards,
Truman
On 22/12/2009, at 11:31 PM, Deric Kwok wrote:
> Hi Bruce
>=20
> Thank you so much to explain me in detail. I would like to know about
> this it in case i can get another hosting company
>=20
> Yes. I think the netmask should be 255.255.255.255
> 1/ but why they are using this netmask setting? save ip address?
> then does the router handle many routes in this setting?
> 2/ What is this advantage for the hosting company?
> 3/ If I need more ip in the same server, how it works?
> 4/ Why you said the hosting company is cheap to use this =
configuration?
>=20
> Thank you again.
>=20
>=20
>=20
>=20
>=20
>>=20
>> <SNIP>
>> 2/ lf the network card in server has problem and need change another
>> one, will my ip address change to another ip address also?
>> </SNIP>
>> Yeah well thats how dhcp works, via ma caddy, i guess you can always =
spoof
>> your old mac address.
>>=20
>> <SNIP>
>> 3/ why hosting company is using /32 and dhcp? what is advantage? ls =
it
>> easy for administration?
>> </SNIP>
>> Im guessing because the users are to stupid to understand what a =
subnet
>> mask/gateway is its just easier to get the mac address and assign it =
to a
>> user then let the user assign a ip.
>>=20
>>=20
>> Normally in a co-location setup its not like this, inless its very =
cheap
>> hosting.
>>=20
>> My co-location has the following setup, and this is how MOST networks =
should
>> be run.
>>=20
>> Core router using BGP to transit providers, and other local peers.
>> Switched network useing ospf to handle the routes and also VLAN's for =
the
>> customers subnets.
>>=20
>> So customer should get a vlan assigned to them (which they have no =
need to
>> know what the number is, they are handed a access mode port.
>> Customers also issued a /30 (at least) in most cases a customer will =
get a
>> /29 or /28 depending on what they need.
>> In this case of a /30 its a total of 3 address's
>> 1, GATEWAY (put on the ISP/HOST switch
>> 2, IP ADDRESS FOR SERVER TO USE
>> 3, BROADCAST ADDRESS.
>>=20
>> Heres an eg of a /30:
>>=20
>> Address: 192.168.1.1 11000000.10101000.00000001.000000 01
>> Netmask: 255.255.255.252 =3D 30 11111111.11111111.11111111.111111 =
00
>> Wildcard: 0.0.0.3 00000000.00000000.00000000.000000 11
>> =3D>
>> Network: 192.168.1.0/30 11000000.10101000.00000001.000000 00
>> HostMin: 192.168.1.1 11000000.10101000.00000001.000000 01
>> HostMax: 192.168.1.2 11000000.10101000.00000001.000000 10
>> Broadcast: 192.168.1.3 11000000.10101000.00000001.000000 11
>> Hosts/Net: 2 Class C, Private Internet
>>=20
>>=20
>> Heres an eg of a /29:
>>=20
>> the % ipcalc 192.168.1.1/29
>> Address: 192.168.1.1 11000000.10101000.00000001.00000 001
>> Netmask: 255.255.255.248 =3D 29 11111111.11111111.11111111.11111 =
000
>> Wildcard: 0.0.0.7 00000000.00000000.00000000.00000 111
>> =3D>
>> Network: 192.168.1.0/29 11000000.10101000.00000001.00000 000
>> HostMin: 192.168.1.1 11000000.10101000.00000001.00000 001
>> HostMax: 192.168.1.6 11000000.10101000.00000001.00000 110
>> Broadcast: 192.168.1.7 11000000.10101000.00000001.00000 111
>> Hosts/Net: 6 Class C, Private Internet
>>=20
>> Hope this makes sence.
>>=20
>> Regards,
>>=20
>> Bruce
>>=20
>>=20
>>=20
>=20
