how it routes and network question
bruce at tubes.net.au
Tue Dec 22 06:51:20 CST 2009
I should add; i guess i made some assumption that you were co-locating your
own servers with someone, if this isn't the case, please ignore everything
i'v said ;)
From: Truman Boyes [mailto:truman at suspicious.org]
Sent: Tuesday, 22 December 2009 10:47 PM
To: Deric Kwok
Cc: Bruce Forster; nanog at nanog.org
Subject: Re: how it routes and network question
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.
Even Amazon EC2 instances use private addresses now on the backend ...
On 22/12/2009, at 11:31 PM, Deric Kwok wrote:
> Hi Bruce
> 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
> 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?
> Thank you again.
>> 2/ lf the network card in server has problem and need change another
>> one, will my ip address change to another ip address also?
>> Yeah well thats how dhcp works, via ma caddy, i guess you can always
>> your old mac address.
>> 3/ why hosting company is using /32 and dhcp? what is advantage? ls it
>> easy for administration?
>> 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.
>> Normally in a co-location setup its not like this, inless its very cheap
>> My co-location has the following setup, and this is how MOST networks
>> be run.
>> 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.
>> So customer should get a vlan assigned to them (which they have no need
>> 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
>> /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.
>> Heres an eg of a /30:
>> Address: 192.168.1.1 11000000.10101000.00000001.000000 01
>> Netmask: 255.255.255.252 = 30 11111111.11111111.11111111.111111 00
>> Wildcard: 0.0.0.3 00000000.00000000.00000000.000000 11
>> 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
>> Heres an eg of a /29:
>> the % ipcalc 192.168.1.1/29
>> Address: 192.168.1.1 11000000.10101000.00000001.00000 001
>> Netmask: 255.255.255.248 = 29 11111111.11111111.11111111.11111 000
>> Wildcard: 0.0.0.7 00000000.00000000.00000000.00000 111
>> 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
>> Hope this makes sence.
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