NFS help (.. is definitely needed)

[Otto Haliburton]

> -----Original Message-----
> From: redhat-install-list-bounces at redhat.com [mailto:redhat-install-list-
> bounces at redhat.com] On Behalf Of Otto Haliburton
> Sent: Sunday, August 28, 2005 10:14 PM
> To: fromRHIL at outtacyte.com; 'Getting started with Red Hat Linux'
> Subject: RE: NFS help (.. is definitely needed)
> 
> 
> 
> > -----Original Message-----
> > From: redhat-install-list-bounces at redhat.com [mailto:redhat-install-
> list-
> > bounces at redhat.com] On Behalf Of Greg Julius
> > Sent: Sunday, August 28, 2005 7:36 PM
> > To: Redhat Install List
> > Subject: RE: NFS help (.. is definitely needed)
> >
> > I broke this up to understand it and reply in parts.
> >
> > >not wanting to get into a heavy discussion on this issue, I will just
> > state
> > >this simply.
> > >
> > >My ISP assigns me a IP address, I have a router and through
> > >the DHCP my computer is assigned a local IP address and since I have
> > >connected to my local address I have up to 5 local IP addresses(could
> > have
> > >many more if I liked) under this standard each of the 5 IP addresses
> are
> > >translated to go out the one address assigned by the ISP.
> >
> > This router sounds like a standard router which you can get from
> Linksys,
> > NetGear, et. al.  In comes one wire (the WAN from your ISP) and out goes
> > one
> > or more wires (the LAN).  Many even have an access point built into them
> > to
> > give wireless capability to the LAN.  These things are quite amazing
> when
> > you think about it.  They have multiple Network ports, they accomplish
> > many
> > networking chores, they provide address translation and some firewall
> > capabilities and even wireless.  All in a box between $25 and $125.
> Easy
> > to
> > use and easy to set up.  Reliable as the day is long.
> >
> > <warning>
> > Discourse on DHCP, WAN, LAN, NAT, and SPI forthcomming, skip if you know
> > all
> > about it.  But since this thread is turning into a general education on
> > networking, it feels right to do this.  I hope I'm not insane and
> showing
> > too many flaws in my understanding.  Everyone please jump in where I
> have
> > boned it up.
> > </warning>
> >
> > Most ISPs providing high-speed internet give a dynamic address.  If you
> > are
> > providing services to the internet (say a web-site or an email server)
> > then
> > you will probably need a static IP.  There are a few reasons where you
> > might
> > need one even if you don't provide services to the internet.  Some
> > providers
> > will only give you static addresses and some providers will never give
> you
> > a
> > static address.
> >
> > In any event, the router has the ability to "speak DHCP" to the ISP and
> > request an IP from the ISP (they come out of the box configured that
> way).
> > They can also be configured to respond to a specific static ip if that
> is
> > what your ISP gave you.
> >
> > Some routers have the ability to report to one of the "dynamic DNS"
> > providers (like DynDNS JEff mentions) the IP address assigned by the
> ISP.
> > This gives the ability for the internet at large to find your router
> even
> > though it doesn't have the decency <grin> to stay at a given address.
> > Static IP assignments don't need the dynamic DNS solutions.
> >
> > The configuration of the WAN side of the router, either static or
> dynamic
> > provides some much needed information:  The network address & subnet,
> the
> > router's address as seen from the internet, the router's gateway IP to
> the
> > internet, and a couple (usually two or more) Domain Name Servers for
> > Domain
> > Name resolution.
> >
> > So, for the sake of this discussion, let's say that the WAN IP address
> > (the
> > address of the router as seen from the Internet) is A.A.A.34 (make up
> your
> > own numbers for A.A.A <grin>  For the literal, the A number is between 0
> > and
> > 255).  This WAN IP could have been dynamic or static.  The important
> thing
> > is that there is one.  There will also be the other values as mentioned
> > above.
> >
> > That covers the WAN side.  Now for the LAN side.
> >
> > The router usually provides DHCP services to the devices attached to the
> > LAN
> > by wires or wireless.  The router can also accept devices that have a
> > fixed
> > IP address.
> >
> > On the LAN side, you would commonly get a set of addresses starting with
> > 192.168.0.x or sometimes 192.168.1.x - I've seen both - if the address
> > were
> > generated by an out of the box router by DHCP.  x is usually a value
> > starting at 100 and going up.  Supposing you have two devices attached,
> > then
> > one could be 192.168.0.100 and another could be 192.168.0.101.  If you
> > configure the DHCP service provided by the router you can end up with
> > anything.  Note that the router also has a network address on the LAN,
> > usually 192.168.0.1.  This is the address of your router as seen from
> > inside
> > your network.
> >
> > OK, now we have a wire on the right (The WAN) and wires on the left (The
> > LAN).  The WAN side of things can be thought of as the Internet.  The
> LAN
> > side of things can be thought of as the internal network or Intranet.
> >
> > >From the point of view of the internet, all of your computers have the
> > same
> > address, Namely A.A.A.34, the address of the WAN IP on your router.  The
> > crowd on the internet never sees your internal 192.168.0.x address.
> >
> > So, how does your computer attached at 192.168.0.100 carry on a
> > "conversation" with a computer on the internet?  More to the point, how
> > does
> > a response from something on the internet get to  your PC if all of the
> > PCs
> > on your internal network appear to have the same address?  That's NAT's
> > job.
> >
> > NAT is Network Address Translation.  ** Note:  I am about to really
> > simplify
> > here to avoid confusing on exactly how this works  **  When you start a
> > "conversation" with an Internet service (say your email at your ISP)
> your
> > PC
> > says I want to talk to IP B.B.B.B (which is the IP provided by some DNS
> > server for the name of your email server on your ISP).  The first thing
> > your
> > computer does is look up to see where it should send it.  It doesn't
> know
> > so
> > it sends it to the gateway for your network.  The gateway will usually
> be
> > the router (remember the 192.168.0.1 address from earlier?).
> >
> > The router then takes note of which computer the message came from and
> > where
> > it was going (it remembers), it then translates the internal network
> > address
> > into a variation of the A.A.A.34 address and then sends the message
> along
> > on
> > to the next hop which will be the gateway address of the WAN.
> >
> > When the reply comes back, the router looks up where it came from and
> > where
> > it was going (the variation of the A.A.A.34), "untranslates" the
> addresses
> > and sends the message to the appropriate computer.
> >
> > That's NAT in a nutshell.
> >
> > Now what about when somebody sends something to A.A.A.34 out of the
> blue?
> > Usually, because it doesn't know who it was intended for (can't find
> > anything in it's memory about it) it throws it away.  This feature is a
> > part
> > of what is called SPI (Stateful Packet Inspection).  When you send
> > something
> > out (an outgoing packet), the router remembers who, what, when, how.
> When
> > a
> > reply comes back (an incoming packet) the who, what, when, and how is
> > compared to prior outgoing packets looking for a match.  If it doesn't
> > find
> > it, and the router isn't configured to do something special with it,
> then
> > it
> > just throws it away.  This is a basic firewall feature and helps to
> > prevent
> > uninvited outsiders from getting into your network.
> >
> > That's SPI in a nutshell.
> >
> >
> > >When it assigns
> > >me the one IP address it assigns my IP address to two DNS IP addresses
> > and
> > >it also assigns a gateway.
> >
> > A bit of care here on the terminology.  Your ISP assigned your router a
> > network address & subnet, an IP, and a gateway and INFORMED it of two
> DNS
> > addresses that it could use for retrieving IP addresses from Domain
> names.
> > It didn't send anything to the DNS for you.
> >
> > >The ISP can change the IP address it assigns to
> > >me(this assignment is a dynamic assignment) anytime it wants and it
> will
> > be
> > >transparent to me because the DNS to which this IP is assigned is
> updated
> > >with the IP address and since it is transparent somebody in China can
> > still
> > >send a message or connect to my network and they don't need to have the
> > new
> > >IP address that is assigned.
> >
> > Sigh.  Not exactly right.  Yes, the ISP can, will, and does change the
> > address which gets assigned to your router.  It does not send anything
> to
> > the DNS.  Period.  Your router may send something to a DynDNS type
> > service,
> > but you can rest assured that your ISP did not.
> >
> > For clarity, I would like to find out why you think your address is
> > getting
> > assigned to the DNS so somebody in china can get to you?
> >
> > I'm not denying that they can send you messages via email or even via
> some
> > instant messanger or something of the sort, but not by the name of your
> pc
> > which is inside your internal network.
> >
> > >Now on my local network I can have the same
> > >setup.  I can have my own DNS server that I assign my local IP to and
> it
> > >resolves the issues for my local network.  On local networks
> arbitration
> > >goes on and somebody declares I'm the boss and I will handle all of
> this
> > >info and if he drops out then the arbitration happens again and
> somebody
> > >else becomes boss, etc etc.
> >
> > This sound extremely like NETBIOS processes and is not a function of
> > TCP/IP
> > at all, nor even of the internet.  Are you sure you are not confusing
> the
> > two as they are very similar in purpose and function?
> >
> > Yes, you can set up a DNS on your internal network.  All it takes is a
> > host
> > to run it on.  Yes, you can put in your DNS the IP addresses of the
> > machines
> > on your network.  This is manually done usually.
> >
> > There are even some routers which now contain am mDNS which works in
> > conjunction with their internal DHCP and gives a "Dynamic DNS" ability.
> > The
> > Dynamic part is the Address assignment from DHCP and a real-time update
> of
> > the DNS of that assignment data.  But even in this case, the mDNS is
> being
> > updated by the DHCP and not by the host.  I know it sounds like
> splitting
> > hairs, but of such is the network made.
> >
> >
> > The rest of the statement is not DHCP nor DNS and sounds like NETBIOS.
> >
> > >The DNS declares himself to be the boss of the
> > >5 computers on my local and does all of the resolutions for my network
> > and
> > >communicates with the outside world to resolve the issues.
> >
> > This would definately be NETBIOS. It isn't DNS.  While DNS may give name
> > resolution services, it doesn't declare itself boss.  The Network setup
> > data
> > provided by DHCP or by manual configuration says where to go look for
> name
> > to address resolution.
> >
> > >One of the
> > >issues that you mention is true for domains like .com, .net, and etc.
> > ???
> >
> > >but
> > >that is only part of the answer the other part is the routing and
> routing
> > >tables and these are important in the address resolution.
> >
> > Actually, routing and routing tables have nothing to do with name to
> > address
> > resolution.  Nor DHCP.
> >
> > Routing and routing tables are the underlying mechanism for getting a
> > packet
> > from point Address A.A.A.A to B.B.B.B  This involves a lot of things
> like
> > address resolution protocol and transmission metrics and RIPs and such
> > which
> > I won't even begin to touch.  My understanding of that is shakey at
> best.
> >
> > DHCP is the assignment of an internet address (your WAN or LAN addresses
> > for
> > example) to a particular host or device.  This device may be on your
> > internal network or perhaps your router address from your ISP.
> >
> > DNS is concerned with mapping a name (POP.EXAMPLE.COM) to an internet IP
> > address (the A.A.A.A or B.B.B.B).
> >
> >
> > >While I don't
> > >disagree with you completely.  There are definitely holes, I am not a
> > >expert, but you can check any ISP assignment to see that the structure
> I
> > >presented above is alive and working.
> >
> > Jeff makes excellent points about the internet and shows a keen grasp of
> > the
> > issues facing dynamic domain name service issues on the internet as a
> > whole.
> > I think Jeff was thinking mostly about the internet at large in his
> > response.  LANs have a bit more flexibility and that is where this
> > discussion originally started.
> >
> > Regarding your claim that that's how it works, I just don't see it.  I
> > don't
> > know which part of the internet you are using, but mine doesn't work the
> > way
> > you describe.  Neither the parts inside my three LANs nor the parts of
> the
> > internet I interface with connecting my LANs to the internet and while
> > providing web hosting to my clients.  I get the feeling you are mixing
> > NETBIOS and DNS and DHCP and such in a big mash.
> >
> > >SNMP is a part of what you presented
> > >so I am not completely positive about all of this but there is chaos
> > going
> > >on when you decide to send a message, cause a route has to be setup and
> > it
> > >is this arbitration between the DNS that determine how to setup this
> > route.
> >
> > I did a search on the original message and don't find SNMP mentioned.
> > Simple Network Management Protocol is a tool used to manage the devices
> on
> > the network and to diagnose the network when it is down or not working
> > correctly.  I don't really use it yet as my needs have been simple to
> this
> > point.  Soon, but not now.
> >
> > -g
> >
> >
> you have gone through what you think is a heavy analysis, let me now give
> the the simplest and the skinny about how you isp works, when your router
> comes up it goes to the DHCP for the ISP and get assigned a IP address
> this
> ISP address is usually assigned to computername.state.city.isp.domain in
> the
> dns now you can go from there
> 
> 
I forgot to attach the mac address which is what makes it unique in the dns.