Multiple ip's with renting a server

[Cruorzy]

Hey guys quick question just to make sure.

 

Most of the dedicated server hosters offer multiple static ip's so you can have like 5 different ip's.

 

Does this mean that multiple NIC's are installed in the server and what would be a basic use of it out of curiosity.

 

Thanks!

[Eniqmatic]

It depends on their setup.

 

When you are say "dedicated server" are you talking your renting out a whole physical machine, or a VM that runs on a machine?

[Cruorzy]

Well they are called oneprovider, i think it is a physical machine. Not sure i will look it up soon.

[Eniqmatic]

I would most likely say no, in a basic form, they will most likely just do a NAT from whatever firewall solution they are using to the machine they are providing you access with.

[mariushm]

Usually servers have two network cards, one for connecting to the internet through their routers and the second card available in case you may want to rent additional servers in the same rack and create a local network between the servers using that separate network card. This way you'd have 1 gbps unmetered between your own servers, and whatever connection you choose to the Internet.

You can bind multiple IPs to one network card, and it's very useful for some situations.

For example, you could configure an email server and bind it on one IP and set the reverse dns for that ip to mail.domain.tld or whatever domain you decide to use.

If you run a commercial website, some SSL certificates require static IP and you may not want to use the same IP you use for mail server so there goes your second static IP.

Some also prefer to assign a static IP for FTP servers.

 

But basically, the reason they can give you up to 5 IPs is pretty much because your server is connected to a switch port on a VLAN, which reserves a block of 8 IPs (or was it 7, i forget)... this way servers on same switch in the rack can't connect directly to your servers on same switch, it's like having the big switch separated in several tiny separate switches.

Some ISPs no longer give you these static IPs right from the start, you have to request additional ones and give justification, and they usually charge something like 1-3$ a month for each additional IP besides the first one or first two IPs.

 

[KuJoe]

26 minutes ago, Cruorzy said:

Hey guys quick question just to make sure.

 

Most of the dedicated server hosters offer multiple static ip's so you can have like 5 different ip's.

 

Does this mean that multiple NIC's are installed in the server and what would be a basic use of it out of curiosity.

 

Thanks!

Nope, all OS'es allow more than one IP per physical NIC. I have servers with over 400 IPs on it with only 2 network connections (2 NICs bonded for redundancy).

[brwainer]

1 hour ago, KuJoe said:

Nope, all OS'es allow more than one IP per physical NIC. I have servers with over 400 IPs on it with only 2 network connections (2 NICs bonded for redundancy).

I'm aware of why you would have multiple IPs per server (most of our servers at work have 10-20 public IPs and 20-50 private ones) but can I ask what the use case is to have over 400?

[Eniqmatic]

15 minutes ago, brwainer said:

I'm aware of why you would have multiple IPs per server (most of our servers at work have 10-20 public IPs and 20-50 private ones) but can I ask what the use case is to have over 400?

Depending on the size of the company (assuming its a business) then they may rely on this many public facing different services.

[KuJoe]

1 hour ago, brwainer said:

I'm aware of why you would have multiple IPs per server (most of our servers at work have 10-20 public IPs and 20-50 private ones) but can I ask what the use case is to have over 400?

VPSs, each with at least one dedicated public IP address.

[brwainer]

45 minutes ago, KuJoe said:

VPSs, each with at least one dedicated public IP address.

Oh to me that isn't exactly hundreds of IPs on a single interface because no one OS is seeing them all - that's like saying a CMTS might have a thousand IPs because it can handle a thousand modems.

[KuJoe]

9 hours ago, brwainer said:

Oh to me that isn't exactly hundreds of IPs on a single interface because no one OS is seeing them all - that's like saying a CMTS might have a thousand IPs because it can handle a thousand modems.

I think the client was mainly asking about a single physical connection for multiple IPs. I do have some VPSs with over 300 IPv6 addresses assigned to a single interface though which fits the 1 interface to many IPs scenario.

[tt2468]

15 hours ago, Eniqmatic said:

It depends on their setup.

 

When you are say "dedicated server" are you talking your renting out a whole physical machine, or a VM that runs on a machine?

A dedicated server is always a physical machine.

 

Most dedicated servers only have one NIC connected. That one NIC can support as many IP addresses as necessary.

[Smite]

The number of IPs assigned to a NIC is based on the subnet given to said nic. Example 192.168.1.20 subnet of  255.255.255.248 this is a subnet of 8 addresses with the last being the broadcast address. and the first is typically the main and the rest are hosts. 

[brwainer]

1 hour ago, Smite said:

The number of IPs assigned to a NIC is based on the subnet given to said nic. Example 192.168.1.20 subnet of  255.255.255.248 this is a subnet of 8 addresses with the last being the broadcast address. and the first is typically the main and the rest are hosts. 

That tells the OS what other IPs are in its subnet - NOT how many IPs the OS can use. Typically you have to tell the OS the subnet mask for *every* IP (although there may be some defaults based on Class A,B,C)

[Smite]

20 hours ago, brwainer said:

That tells the OS what other IPs are in its subnet - NOT how many IPs the OS can use. Typically you have to tell the OS the subnet mask for *every* IP (although there may be some defaults based on Class A,B,C)

Right, I didn't elaborate because I didn't think it was necessary but this is the separation of Server\Network. Simple answer to the question is Yes you can have multiple IP's for nics. Notice the add button on the Pic.