Dopey Dora's home networking questions

Discussion in 'Networking, Telephony & Internet' started by broccoli, Jul 11, 2019.

  1. broccoli

    broccoli Member

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    I know enough to have things working. My eyes roll around in their sockets when anyone starts discussing networking.....

    I have several NAS boxes (qnap and synology). They have more than one ethernet port. You can "combine" multiple connections such as described in this https://www.synology.com/en-global/...p/DSM/AdminCenter/connection_network_linkaggr. The qnaps say "The NAS services run on all available network interfaces by default. To bind the services to one or more specific network interfaces (wired or wireless) enable service binding and configure the settings. The users will only be able to connect to the services via the specified network interface(s)".

    I think I combined things before, just to see what happened (nothing noticeable, from memory). My questions:

    1. is this worth doing as in does it make things faster or better somehow?
    2. if yes, are there settings on the attached network cards or NAS that should be enabled/disabled to make it "work" properly?
    3. I have my windows home server doling out specific IP addresses and I've got a hosts file on each client computer, so that my computers always have the same address and I can access them by name (I used to set each client to have static, not dhcp, but it was a pain in the neck having to change things on each computer, instead of just on the server, so when I figured out how to do it on the WHS, I started doing that instead). What actually happens when you link up multiple ethernet connections, insofar as getting/having an IP address? At the moment, on the DHCP server function setting section on the WHS machine, I put in the mac address of the computer and say what IP address I want it to be given. If you're linking up the ports, is there a way of handling this on the DHCP reservations (each port still has its own mac address). Does just picking one do the trick? Should I put a reservation for each mac address with the same IP address (not sure it'd even let me do that?????)

    Separate question:

    What exactly are "jumbo frames" and do I want them?

    Thanks.
     
  2. Doc-of-FC

    Doc-of-FC Member

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    if you're in the territory of 5+ active users, then bonding / load sharing may be worth it, otherwise a single magic blue spaghetti cable is fine.

    jumbo frames are an older means of dealing with getting to gigabit speeds by reducing the cpu load for calculating network overheads, these days with network card offloading and multiple cpu cores its mostly unneeded unless you're trying to squeeze out every remaining single digit % point of performance, it can also introduce path MTU discovery issues leading you to more headaches.
     
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  3. OP
    OP
    broccoli

    broccoli Member

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    Thanks so much. :)
     
  4. evilasdeath

    evilasdeath Member

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    Yeah lag (link aggregation) only helps if you have multiple concurrent users, as with most channel bonding methods is by host so host A will use port A and host B will use port B, so if host A and B are talking they could theoretically both get 1 gbit. Its hard to control thou often host A and B will end up on port A etc (think about it there are 4 combinations) so when you apply it 50 times you will likely get a close to 25/25 split.

    Yes your switch needs to support it as well, most managed switches do.


    As for jumbo frames.
    Standard ethernet frame is 1518bytes, 18 bytes L2 header, 20 bytes IPv4
    ~2.5% overhead.

    Jumbo definition varies can be upto 9600 but often 9000.
    same headers
    so 0.4% overhead

    so if you could flatline the link, it would be the difference between 975mbit payload rate, and 995mbit, plus applicable device calculation overheads. Since you need to do calculations 5 times less. But often more hassle than its worth.
     
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  5. OP
    OP
    broccoli

    broccoli Member

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    Thanks, yeh, it seems to often be the case. I've never been worried about things being slow to be looking for ways to jazz things up, it's just when there's something there, I like to learn stuff.
     
  6. Aetherone

    Aetherone Member

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    In the modern era of SMB3 (assuming your NAS'es and OS'es both support it), there can be a benefit from multiple links for a single user. It's not exactly a guaranteed outcome and can be damn finicky about deciding to work.

    Most home level NAS'es also struggle to have the IOPs required to service multiple clients at speeds that exceed 1Gpbs so the multiple links can be mostly redundant in all cases.
     
  7. OP
    OP
    broccoli

    broccoli Member

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    In which case, I can't be bothered with it. :D
     
  8. Aetherone

    Aetherone Member

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    On the upside, it's not hard to test. Update to a current build, tick the SMB3 box on the NAS, be running a recent version of Windows, copy, paste and ...?
     
  9. OP
    OP
    broccoli

    broccoli Member

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    yeh, nuh. :D
     
  10. OP
    OP
    broccoli

    broccoli Member

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    Me again. Rather than start a new thread, I have another question....

    I have Windows Home Server 2008 running on an N40L. This has a DHCP Server role and I've reserved IP addresses for my computers so that they always have the same number. There's a pool of addresses that can be doled out, and then there's the reservations for the computer/numbers. Then there's a list of "address leases". This list may or may not be accurate. It has the reservations, even if that computer isn't on, or connected, and it has the active reservations. If a reservation is inactive, the server might have given that reserved address to something else, it doesn't really "reserve" it for the exclusive use of the computer it's reserved for. It might also have given a "not reserved but in the address pool" IP address out, these don't seem to be included in the "address leases" list.

    Is there a way of seeing what IP addresses are active and who has it/who is on the network and what their IP addresses are? Either in the Server Manager section or elsewhere? (reason is that I've just connected a backup computer and it isn't responding to it's reserved number. It might not have got an address at all and have a 169. number, or the server might have doled out something else. Is there a way of finding out if it's doled out something else (without going in there and hooking up a monitor)? Thanks.
     
  11. waltermitty

    waltermitty Member

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    can you not go on the backup computer and switch on dhcp & check the ip?
     
  12. OP
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    broccoli

    broccoli Member

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    it's "headless" I have to hook up a monitor.
     
  13. evilasdeath

    evilasdeath Member

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    ping it's hostname, windows may suck but it usually does a good job of publishing it to dns so it can be reached. Either on Ipv4 or often on IPv6 which is all auto discovery (if you have it enabled)

    If it does have a 169 address then it wont publish to dhcp at all, since dhcp server doesn't know about it.

    The other thing you can do is reboot it and listen on your local pc with wireshare for the bootp(dhcp) requests. IF bootp fails it will gratuitious arp with its ip that it chooses (to prevent double allcoation)

    As for leases, if you reserve it then it also removes it from the pool to allocate, as such a device switched on will not take a reserved IP even if that host is off.
     
  14. OP
    OP
    broccoli

    broccoli Member

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    I did that before, it was unreachable (I don't really have a properly working dns server, so that publishing stuff you speak of probably doesn't happen)

    I don't really understand all the arp barp whatever. It's easier just to go and hook up the monitor than get my head around something new.

    I'm not sure the reservations are reserved. If it's "inactive", somebody else can get the number, I'm pretty sure, because I've sometimes had the wrong computer on the other end of a request.
     
  15. evilasdeath

    evilasdeath Member

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    Maybe the windows DHCP server is stupid because i thought most excluded it from allocation if it was reserved but maybe windows is special :p
    Maybe setup your DHCP scope to be the first 128 IPs and the reserved to be in the top 128 ie 192.168.0.1>127 = DHCP address. 192.168.0.128->254 are reserved then it wont.

    As for DNS, windows does its own etc so while its not full DNS, hostnames work. (its how your smb shares can open a host by name, and you can go through the computer browser)

    But yes sometimes for all the things that dont work properly sometimes a monitor helps heaps, its why things like ipmi are great
     
  16. OP
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    broccoli

    broccoli Member

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    It's not a huge drama things getting the wrong numbers, usually it's fine, I've just changed a whole heap of things about, that's all, and just rehooked up this backup computer.

    Mine know their names because I've got a hosts file. Otherwise, they'd have no clue.

    It's not a huge drama hooking up the monitor to see what's going on, it's just that the NASes can be located, and their ip addresses disclosed (even if they're not on the same numbers), by the programs that the nas people supply. There should really be something similar to use in windows, a "tell me what's out there" command.

    Thanks anyway.
     

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