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Thread: Help me understand a couple of networking things I encountered during extraction

  1. #1
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    Help me understand a couple of networking things I encountered during extraction

    This is a bit long so please bear with me and help me understand what happened for future reference. My questions are in bold.
    We took over an existing ra2 install so I tried to extract the programming. The system was connected to the home network via a 15 port switch and god only knows how it was connected to the rest of the house. Customer wanted to change some scenes and also mentioned her apps hadn't worked in 2 years.


    • First, I tried the current version 13.x and wishfully attempted to extract but it said no main repeater found.
    • Next I did an IP scan of the network starting from 192.168.5.1 (how the network was setup) and it showed Lutron on 192.168.5.198.
    • Great. I used a browser to go to 192.168.5.198, typed in lutron and lutron for username and password and saw that it was with database version 9.2 and so I installed it.
    • Attempt #2 at extracting the database also resulted in "no repeater found".
    • I called tech support and he walked me through setting up static IP and connecting directly and I was able to extract the programming. Success!


    Oddly enough, the address on the extracted program was 10.0.0.x or something and after speaking with the customer I guess the same AV company who originally installed the system changed their network equipment and presumably never bothered changing the settings on the ra2 system so I guess it was a different network scheme. So far so good.

    Anyway, I connected the repeater back to the network and attempted to change the settings to match the current settings. Once again, wifi failed so I had to connect my laptop via ethernet in which case it found it on the first try. I changed the setting to DHCP and again 192.168.5.198 was chosen for it. To be honest, I have no clue what the DHCP range was on the network but since the customer was going to use the app, it needed a static IP so I turned off DHCP and the address changed to 192.168.5.201 BY IT SELF! How did it change by itself? Was the Ra2 software smart enough to somehow communicate with the router to pick an address that was outside of DHCP?

    I then went about making the requested changes and uploaded them while still connected to the home network via ethernet and all went well, but I noticed that if I switched to wifi, it would no longer work. I could go to the HTTP page with wifi just fine but not through the ra2 software.

    At this point I went to set up the customers ipads using the name and passwords in the integration section. Whether it was automatic discovery or me manually typing 192.168.5.201, the app could not location main repeater. I tried 2 ipads plus my own Android phone with the Home+ app and nothing. I tried the browser again to make sure the network itself was communicating and sure enough, HTTP worked but not the apps. I gave up and told her maybe the networking people had a firewall blocking it or something and spent an hour making some more scene changes with her and labeling the keypads and just as I was about to leave the house, I noticed my app was connecting! I tried her ipads and iphone and sure enough, self discovery wasn't working but putting in 192.168.5.201 would download the plans and voila. Why did it not work before and an hour later worked out? Does the network somehow needs to update some internal tables or was this a ra2 issue?

    It all worked out but I kind of feel dumb. I'm especially curious whether the router was able to communicate that I had picked a wrong static IP. Thanks!

  2. #2
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    How did it change by itself? Was the Ra2 software smart enough to somehow communicate with the router to pick an address that was outside of DHCP?

    My guess- the previous installer tried configuring that repeater at that static IP, then for whatever reason changed back to DHCP. When you reselected static IP, that stored IP address was automatically recalled.

    Whether it was automatic discovery or me manually typing 192.168.5.201, the app could not location main repeater. I tried 2 ipads plus my own Android phone with the Home+ app and nothing. I tried the browser again to make sure the network itself was communicating and sure enough, HTTP worked but not the apps. I gave up and told her maybe the networking people had a firewall blocking it or something and spent an hour making some more scene changes with her and labeling the keypads and just as I was about to leave the house, I noticed my app was connecting! I tried her ipads and iphone and sure enough, self discovery wasn't working but putting in 192.168.5.201 would download the plans and voila. Why did it not work before and an hour later worked out? Does the network somehow needs to update some internal tables or was this a ra2 issue?

    I'm not surprised. Auto-discovery has trouble on managed networks. I've found that the LHC+ app can be frustrating to set up. It's possible that if you were trying to connect with multiple devices in quick succession that was causing problems for the main repeater, but again, that's just me guessing. Are there VLANs on that network?

    In short, this thread reminds me once again how frustrating network connections with Ra2 tend to be. I recently had a takeover like this and after an hour gave up and did all activation and transfers with a 50' LAN cable and a bunch of running back and forth. Yes there are no firewalls on my PC. Yes I tried my backup wifi router and created my own network. Lutron hardware is unbeatable but the PC software network connection issues are startling - I'll take that over the alternative tho. Once I'm connected everything just works.

  3. #3
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    I believe this network does have VLANs because I was just connected to a switch on the second floor and it's a 3 story house so there had to be many more things on there. The odd thing is that while I was unable to connect via the app, despite putting in the IP address, I could go to a computer and just type it in and it would find it so it's not as if the rest of the network couldn't find it. Auto-discovery still didn't work while I was there.

    And yes, I absolutely love Lutron's hardware (well, their wireless stuff at least), but the networking stuff is always an adventure. There are jobs where everything works exactly as it should- I can use DHCP on wifi and everything is found including connect bridge, and there are times I have to have a long ethernet cable and can't even use my own router and have to set-up static IP on my own computer and pretend it's 1995. Kind of frustrating. They blame networks and wash their hands of it and say "that's just the nature of multi-cast!" but the odd thing is I never have any issues with the older Homeworks Illuminations software.

    Anyway...is there a way to tell what the DHCP pool of a network is without having access to the DHCP software? I've had to guess before by just doing an IP scan and seeing what devices look like they have DHCP (pcs, ipads, etc.) and what things are probably static like cameras and such, but it's probably like 30% accurate.

  4. #4
    Quote Originally Posted by SparkyCoog View Post
    Anyway...is there a way to tell what the DHCP pool of a network is without having access to the DHCP software? I've had to guess before by just doing an IP scan and seeing what devices look like they have DHCP (pcs, ipads, etc.) and what things are probably static like cameras and such, but it's probably like 30% accurate.
    No, there's not a way to do this. The best you can do is scan networks and write code that asks for various addresses, and try to guess the range. But its a guess.

  5. #5
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    Quote Originally Posted by MisterC View Post
    No, there's not a way to do this. The best you can do is scan networks and write code that asks for various addresses, and try to guess the range. But its a guess.
    Correct, there's no feature in DHCP to ask for the range. At least not in any of the many DHCP configurations I've ever come across. And understand that DHCP also means there's potential for a 'pseudo-static' address for devices. As in, a device is configured for DHCP but the DHCP service has a fixed lease set up for it. So that device's hardware address will always get a certain IP address. Note, this leased address does not always have to be from within the normal DHCP lease pool. This is a handy way for 'infrastructure' devices to have a safe fall-back in case their configuration gets reset to factory. I set up leases for anything that has a static address just to avoid reset problems.

    VLANs only add to the complexity. Because if their configuration isn't known ahead of time it can be a REAL problem trying to troubleshoot. Especially if someone starts plugging/unplugging without understanding the VLAN setup. With the advent of modern inexpensive gigabit gear there's really very little reason to bother with VLANs in a residential situation. Better to stick with plain old physical layouts instead of getting fancy with VLANs, for the home anyway.

  6. #6
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    Quote Originally Posted by wkearney99 View Post
    Correct, there's no feature in DHCP to ask for the range. At least not in any of the many DHCP configurations I've ever come across. And understand that DHCP also means there's potential for a 'pseudo-static' address for devices. As in, a device is configured for DHCP but the DHCP service has a fixed lease set up for it. So that device's hardware address will always get a certain IP address.
    See I wonder if that's what happened. According to the ra2 software, it assigned 192.168.1.198 in DHCP mode so for SURE I knew that was in the pool because the router assigned it. As soon as I turned DHCP off, thinking it would then be a 'pseudo-static' address while I scanned the IP addresses again to figure out something better, it was changed to 192.168.1.201 by itself. I've never seen that and I know the previous programmer didn't put that in because they had 10.x.x.x type of setup at first. So that's why I was wondering if there is some sort of communication going on there behind the scenes that figured out 192.168.1.198 was not a proper static IP...

    So far it's working but I guess if the customer suddenly complains that the apps aren't working (it's just a local connection as she didn't want to pay for the subscription or get a connect bridge), I'll ask her to call her network people to give me a proper static IP.

    The problem I have is that I'm an electrician and lighting guy (CS background) and often times I work at a house with either a super complicated network setup by an AV guy who already resents me being there on his/her turf, or worse, it's a house that had networking installed 6 years ago and the company that did it is already out of business or they had a falling out with the customer and nobody remembers anything other than the wifi password. It's rare that I deal with a house with a simple network with a single router and the customer gives me access.

  7. #7
    The term "pseudo-static" isn't really good terminology. It is called a DHCP reserveration, or sometimes a static lease.

    A device that was obtaining IP information from the DHCP server must periodically ask to renew the lease. This is typically done at about 1/2 the time of the lease duration. This allows both sides to know the address is still needed/wanted/available.

    Once you turn off the DHCP server, the server can send out REVOKE messages, and the devices must of course then manage their own IPs. Some will resort to earlier-configured IP information. This is likely where the .201 address assignment came from, but without testing the device, or knowing anything about it, its not possible to state definitively.

    It's tough working in environments where semi-knowledgeable people hack away at the network infrastructure without understanding what they are doing, or the implications. Your customers, who obviously have more mission critical infrastructures than typical network users, really should have a single, reliable network expert (and I'll use that term lightly). Otherwise, the ISP, the A/V guys, the Lighting guys, the brother-in-law, all do their own thing, make a mess of the network topology, leaving it for someone else. You might consider if this is something you want to own/offer as a service.

  8. #8
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    Quote Originally Posted by MisterC View Post
    The term "pseudo-static" isn't really good terminology. It is called a DHCP reserveration, or sometimes a static lease.


    It's tough working in environments where semi-knowledgeable people hack away at the network infrastructure without understanding what they are doing, or the implications. Your customers, who obviously have more mission critical infrastructures than typical network users, really should have a single, reliable network expert (and I'll use that term lightly). Otherwise, the ISP, the A/V guys, the Lighting guys, the brother-in-law, all do their own thing, make a mess of the network topology, leaving it for someone else. You might consider if this is something you want to own/offer as a service.
    I appreciate the explanation that .201 may have just been a newly issued address.

    With the other stuff, in my case, the worst thing that can happen is the customer's app may not work for a few days if the lease is revoked. Really my main purpose that day was to change the programming of the scenes on the keypads and "by the way, our app hasn't worked in 2 years" so I did what I could with the access I had. At least now I am at a much better point and can just tell the network guy exactly what I need. They were without it for more than 2 years since the last "network expert" got paid lots of money to install a new network and didn't update the Ra2 system and never even bothered putting stickers on the keypads, much less engraving. We are there on a monthly basis so we can get with the networking guys and resolve this issue.


    I certainly agree that having one person in charge of their area of expertise is the best policy and many of our customers have "a guy" and we are all on good terms and can just call each other when there is an issue but but I live in the real world, there are customers who don't want to spend the money.

    As long as we're mentioning people working with things they're not supposed to, from an electrician's point of view, I see many AV guys who have never touched electrical, don't understand load types, 4-way wiring, etc. get the lighting job and then either do the work themselves or use an unlicensed cousin who's supposedly a journeyman and is doing unlicensed side work. That actually has the potential to injure someone so it goes both ways!

  9. #9
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    Quote Originally Posted by SparkyCoog View Post
    See I wonder if that's what happened. According to the ra2 software, it assigned 192.168.1.198 in DHCP mode so for SURE I knew that was in the pool because the router assigned it.
    Not necessarily. An address handed out from a DHCP server can be from the pool or it can be a reserved lease (which may or may not be from within the same pool).

    As in, 192.168.1.64-253 are set up as a pool. One lease is setup for 192.168.1.88 (in the pool) but another is setup for 192.168.1.30 (which is NOT in the pool). This way if the device expecting to use the .30 address suddenly shows up NOT using it, but one from the pool then you'd know the hardware address lookup for it in the lease is no longer valid. As in, the device was replaced and no longer has the same hardware MAC (media access control) address (nothing to do with Apple computer gear).

    Not all DHCP server configurations will let you assign leases outside of the pool range. Some will, some won't.

    And yes, 'pseudo-static' is the same thing as setting up a reservation. The idea here is belt-and-suspenders. You set up a lease but then also configure the device with the same IP address as static. This way if the device gets factory reset and reverts back to DHCP leasing then it'll still get the same IP address from the server. In theory you don't have to configure the device as static if there's a lease set up. Unless, of course, something happens that causes the DHCP server to be offline at the point when the device needs a lease response. As in, power outages. The router/DHCP server may not come back online fast enough for embedded devices making lease requests. "Pseudo-static" helps avoid that scenario.

    Granted, if someone monkeys around with the router and changes the IP address range then all bets are off. See later comment regarding lighting, av, brother-in-law shenanigans.

    Quote Quote
    As soon as I turned DHCP off, thinking it would then be a 'pseudo-static' address while I scanned the IP addresses again to figure out something better, it was changed to 192.168.1.201 by itself. I've never seen that and I know the previous programmer didn't put that in because they had 10.x.x.x type of setup at first. So that's why I was wondering if there is some sort of communication going on there behind the scenes that figured out 192.168.1.198 was not a proper static IP...
    Remember "Lost in Space"? When the robot flailed it's arms yelling "Danger Will Robinson!"? When you start seeing use of 10.x.x.x ranges you better PRAY the people doing the configuration knew WTF they were doing. There's nothing magical about it but moving from Class C 192.168.x.x/24 to Class A 10.x.x.x/8 martian ranges is not without complications. Least of which being different subnet masking. There are many consumer network devices that may 'react poorly' to operating on a none /24 subnet. But with the advent of IoT (internet of things) there's a lot more devices connecting to home networks. Thus the traditional 253 device limit of a /24 Class C might not be enough.

    Add multicast into the mix and things get complicated. Add VLANs and... <see previous robot panicking mode>

    And are you certain there's no other device on the network that might be handing out it's own DHCP addresses? Don't rule out there being another access point or other networking gear that's been left mis-configured.

    Quote Quote
    So far it's working but I guess if the customer suddenly complains that the apps aren't working (it's just a local connection as she didn't want to pay for the subscription or get a connect bridge), I'll ask her to call her network people to give me a proper static IP.

    The problem I have is that I'm an electrician and lighting guy (CS background) and often times I work at a house with either a super complicated network setup by an AV guy who already resents me being there on his/her turf, or worse, it's a house that had networking installed 6 years ago and the company that did it is already out of business or they had a falling out with the customer and nobody remembers anything other than the wifi password. It's rare that I deal with a house with a simple network with a single router and the customer gives me access.
    If they're too cheap to pay for a sub or a bridge then it's no surprise to hear of past 'falling out' problems. You're just the unlucky guy this time around.

  10. #10
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    Oh and while we're on leases and Class C networks, lots of SoHo/consumer routers come with either a very small range or the whole range. The small range ones are problematic in that eventually devices start stepping on each other or some can't get an address at all, or only some of the time (when the others aren't on the network). This can be maddeningly difficult to troubleshoot if you don't first check the size of the pool and number of leases already assigned from it. A fully assigned set of addresses is a BIG red flag when it comes to intermittent networking problems. It's also a good indicator that half-assed attempts to work around it are likely to have been tried...

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