Re: Network basics

In article <1h66luo.1iwgfk41xog4qoN%dempson@xxxxxxxxxxxxx>,
dempson@xxxxxxxxxxxxx (David Empson) wrote:

> Norm <NOSPAM@xxxxxxxxxxxxx> wrote:
>
> > In article <3tvam8Fufju5U1@xxxxxxxxxxxxxx>,
> > Ian Gregory <foo@xxxxxxxxxxx> wrote:
> >
> > > On 2005-11-15, Norm <NOSPAM@xxxxxxxxxxxxx> wrote:
> > > > Trying to figure out why Retrospect sometimes works and sometimes
> > > > doesn't for one client that is now connected wirelessly (via an Airport
> > > > Base Station connected to our gateway router).
> > > >
> > > > A couple of basic networking questions:
> > > >
> > > > If I have 2 computers on a LAN (hope I'm using that correctly) connected
> > > > thru a "gateway router", should I be able to "see" them (one see the
> > > > other) whether I have file sharing turned on or off?
> > >
> > > Depends what you mean by "see", but in general, yes. Turning file
> > > sharing off will not prevent FTP, ssh, ping, IMAP, HTTP etc from
> > > working between the two machines.
> >
> > I have all Sharing Services turned off.
> >
> > Should I still be able to connect to that computer (that is what I meant
> > be "see", sorry) so that it will be visible in the Finder Network window?
>

OP responding.

Thank you very much for all the info. Very, very helpful.
Comments follow.

> Not with all sharing services turned off. Finder's Network window will
> only show machines which are advertising their presence for the purposes
> of connecting to them using a file sharing protocol (Mac or Windows file
> sharing).
>
> This does not affect the ability of the computers to communicate with
> each other using other protocols (many of which aren't controlled by the
> Sharing panel in System Preferences).
>
> For example, you could run iChat on both computers and use
> Bonjour/Rendezvous to chat between them, even if all sharing services
> are turned off on both computers, and neither is visible in the other's
> Finder Network window.
>
> Similarly, Retrospect Client should continue to work. File Sharing has
> no effect on this. You can stop Retrospect Client from communicating
> with Retrospect by turning it off (run the client application and click
> the Off radio button).
>
> You can also prove whether the computers are able to communicate with
> each other reliably by using Network Utility (in the Utilities folder)
> and doing a "Ping" test. This works by sending a message to the other
> computer, which echoes it back again. Your computer will keep sending
> pings for a few seconds, and will show the results (how many replies
> were received). You can also do a continuous test and observe the
> results over a longer period.

Performed the test. Worked as you describe. Thanks
BTW, Is there a way to test speed? Curious as to network speed via
ethernet versus via Airport.

>
> In order to do this, you need to know the IP address of the other
> computer. You can find this out in several ways. My preferred method
> is to use System Preferences (on the other computer): look at the
> Network settings, double-click on the primary network connection (either
> Ethernet or Airport as appropriate), and select the TCP/IP tab. The IP
> address should be shown near the top of the window, e.g. something like
> 192.168.0.50 or 10.0.1.50, depending on how your network is configured.
>
> The results should look something like this if the connection is
> currently OK:
>
> [begin quote]
>
> Ping has started ...
>
> PING 192.168.23.253 (192.168.23.253): 56 data bytes
> 64 bytes from 192.168.23.253: icmp_seq=0 ttl=155 time=0.764 ms
> 64 bytes from 192.168.23.253: icmp_seq=1 ttl=155 time=0.785 ms
> 64 bytes from 192.168.23.253: icmp_seq=2 ttl=155 time=0.794 ms
> 64 bytes from 192.168.23.253: icmp_seq=3 ttl=155 time=0.786 ms
> 64 bytes from 192.168.23.253: icmp_seq=4 ttl=155 time=0.791 ms
> 64 bytes from 192.168.23.253: icmp_seq=5 ttl=155 time=0.791 ms
> 64 bytes from 192.168.23.253: icmp_seq=6 ttl=155 time=0.789 ms
> 64 bytes from 192.168.23.253: icmp_seq=7 ttl=155 time=0.782 ms
> 64 bytes from 192.168.23.253: icmp_seq=8 ttl=155 time=0.797 ms
> 64 bytes from 192.168.23.253: icmp_seq=9 ttl=155 time=0.789 ms
>
> --- 192.168.23.253 ping statistics ---
> 10 packets transmitted, 10 packets received, 0% packet loss
> round-trip min/avg/max/stddev = 0.764/0.787/0.797/0.009 ms
>
> [end quote]
>
> The key piece of information is the second to last line, which shows
> that there were no errors.
>
> You can run the same test on both computers at the same time.
>
> If you use the "continuous" option, you won't get a summary, but instead
> have to watch for any missing sequence numbers in the list of responses.
>
>
> To address your original question as to why Retrospect Client might be
> working intermittently, I need more information on your network
> configuration. I take it that Retrospect itself is on the wired LAN, as
> are other clients which are working OK. These are presumably connected
> to the internal side of the gateway router, which has multiple LAN ports
> and a single WAN port (i.e. a router with a built-in switch for the LAN
> side). The gateway router is presumably configured to act as a DHCP
> server for the LAN. Am I right so far?
>
> 1. Is the Airport base station also connected to a LAN port on the
> router?

Yes.

>
> 2. Is the connection between the Airport base station and the router
> using the LAN port or WAN port on the Airport base station? (The LAN
> port has a symbol which looks like a pair of sideways pointing arrows,
> the WAN port looks like a ring of circles.)

LAN port.

>
> 3. Is the Airport base station configured to act as a DHCP server for
> Airport clients, or is it simply bridging between the LAN and wireless
> network? In my experience, you get much more reliable operation with
> this sort of network configuration by turning off the "distribute IP
> addresses to wireless stations" option in Airport Admin. The end result
> is that the Airport clients get their IP address assigned by the router,
> and they are on the same subnet (which may be important for Retrospect).

Set to not distribute addresses.

>
> 4. Which variant of Retrospect are you using? (Desktop, Workgroup or
> Server.)

Retrospect Backup 6.0.204

>
> 5. What version of Retrospect are you using (e.g. 4.3, 5.0, 5.1, 6.0,
> 6.1) and what version of Retrospect Client?

Client 6.0.109

>
> 6. What operating system versions are running on the Retrospect machine
> and the misbehaving client?

On the Retrospect machine: 10.3.9
On the Client: 10.3.5

>
> 7. Are you using Retrospect's Backup Server feature (backup on request
> by the client) or is the backup done using a normal Retrospect backup
> script (scheduled or run manually)? (I doubt that this would make a
> difference.)

Via scheduled script.

>
> The problem might be caused by the misbehaving client's IP address
> changing from time to time, due to the DHCP server not assigning it a
> consistent address. If Retrospect is remembering the client's old IP
> address, it might not "see" the client when it reappears on a new IP
> address, but would "see" it again next time it recovers the old address.

I did notice that my wife's machine (the client) lost Airport connection
for a time yesterday after I posted this question. I turned Airport On
and Off on her computer but it took several times for the AEBS to show
up and connect by default. So I suspect you are correct. Not sure why it
lost connection nor why not visible when turned Off and On but.....maybe
bad airwaves that day. ;)

Thanks for all the help and the education. I'm about to get a second
AEBS to extend the range and this information will be helpful as I
configure and test.

Thank you.

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