Friends,
I am a newbie to certain real world networking concepts since I have no
hands on experience in network deployments.
And OpenBSD man pages unfortunately are not clear enough for me.
Perhaps I am daft but I would gladly rewrite them for the benefit of ppl like
me...
I also read FreeBSD man pages, googled and read wikipedia too. Still no
joy.
Anyway I have few more questions, but let me begin with these.
1) What exactly is the difference between tun(4), gif(4) and gre(4)
interfaces?
As I understand it, gre is a Cisco tunneling mechanism for generic IP
encapsulation. tun is a generic network device useful for setting up tunnels,
but how?
And gif can be used for setting IP in IP tunnels.
But frankly I am not able to get any further with these statements.
How are these interfaces used in practice? I know that gre is useful
for PPTP traffic.
And that gif can be used for IP in IP for instance, something like
IPsec. What about tun(4)? Is it used as a tunnel interface mechanism from user
space?
Cant you have IPsec without using gif(4)? You can , right?
2) My second question relates to vlan(4). Is my understanding that you
can extend ethernet segments logically across the Internet with vlans correct?
I am sure there is much more to it. I am getting some idea from recent threads
but I am interested in more practical anecdotes as to where it is really useful.
I guess vlans can also be used to split an ethernet broadcast domain
into multiple subnets. Does it help to do this for running pf on VLAN bridges?
Please be gentle if my questions are outright nonsensical.
I think my other doubts on bridging, trunking etc. are not that
troublesome since I seem to have an idea about them.
Many thanks to everyone for taking time to read my e-mail.
regards,
Girish
