ifconfig: difference between creating logical or alias network interface

Applications IP Networking
1

Hi guys,
I have set up multiple virtual FTP servers on a server through one physical NIC. I believe there are to ways; setting logical or alias ip's. I would like to know what is the difference between setting up a logical ip or setting up an alias ip to a physical network interface? Some links to docs would help.

Thanks,
Zaff

2

i'm running Solaris 10. hope thid helps. The options are part of the ifconfig command.

thnks,
Zaff

3

See the man page on ifconfig for more info.

(As an example, I'm using hme0 - your interface may be different)

You can set up a logical/virtual interface by setting the IP or a hostname in a /etc/hostname.hme0:1. If you use a hostname, it has to be in /etc/hosts. And you can either reboot or use the ifconfig command to set up the logical/virtual interface.

ifconfig plumb hme0:1 inet 172.16.1.2 netmask 255.255.255.0 broadcast 172.16.1.0 up

4

So how does this differ from creating an alias of the network interface? i would like to know how creating a logical or an alias differ (pros and cons).

thnks,
Zaff

5

I'm not sure what you mean by 'alias ip'.

If you are talking about setting up an alias in DNS, it is simply

main interface is hme0 with 172.16.1.2 IP with hostname of myserver.mydomain.com
add ftpserver.mydomain.com with same IP in DNS

This would be easier than a virtual interface in my opinion.

If this isn't what you are looking for, you might want to provide more info.

6

sorry if i haven't been too clear in my original question. The ifconfig cmmand has a 'alias' parameter. What does this enable me to do? It seems very similar to a creating a logical network interface, but i can create a logical network interface without having to use the 'alias' command.

Not sure if this is any clearer.

thnks,
zaff