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With Hostnames........ Can I...?

SensivaSensiva Posts: 211
in AMX General Discussion
Hi...

In most of sites , Network Admins insist of using DHCP settings... so I had to build an isolated AMX control network as I always refer to the equipments with its IP address.

I am sure there is another way with the use of host names...
Can I use hostnames with the following:
1- Masters hostname rather than its IP address in NetLinx Comm Setting
2- IP_SERVER_OPEN keyword

- Which device resolves the hostnames to its IP addresses, Switch or Router?
- Is there any speciall setting I should apply to my windows or the Router so it can resolve hostnames?

I know my questions are network related, thats because I am not that expert in networks field, I know what it is enough to install and program simple systems.

thanks

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    DHawthorneDHawthorne Posts: 4,584
    I refuse to accept that as an answer ... I generally ask them to give me a block of static I's I can use.

    Since I don't usually mess with host names, I am not absolutely certain of this, but this is my understanding: you need a DNS server to resolve host names. Your router may support it, it may not; a switch usually won't, and if it does, it has to use the DNS to resolve it. Perhaps someone more network savvy can answer it better.
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    REBUILD_EVENTREBUILD_EVENT Posts: 127
    usually neither switch or router resolve hostnames. usually it's a DNS server doing this.

    although there is a thing called mDNS allowing the resolution of a hostname without DNS server. then it's the host sending sporadic messages allowing the other hosts to resolve the IP address. mDNS is not supported by netlinx masters as far as I know. but I have not been using the hostnames of the Netlinx by now
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    SensivaSensiva Posts: 211
    Well...... Thank you all

    I think , I should say it more clearly..... I mean by resolving hostnames, to resolve the hostnames in the local area network.

    example: I have an A/V matrix switcher (by Knox) - RS232 - , which is very far from from master, so I installed an RS232/IP converter, now I can communicate with this switcher over IP, if that converter is set to acquire IP from DHCP, how can use IP_SERVER_OPEN keyword to establish connection with it? and assume this network isn't connected to the internet.

    Just a D-Link router, connected to a switch where all the system components are connected to it too.

    Very simple network!!
    :)
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    annuelloannuello Posts: 294
    I have the benefit of being an in-house programmer, so I only have to deal with one IT department. They strongly prefer DHCP IPs, which I can fully understand. If we were allowed to use static IPs, there is a possibility that I (or someone else) might enter the IP incorrectly. Imagine tens of 1000's of PCs, where two are jostling for the same IP. When one machine comes online, the other loses it's network connection. Ugh!

    Instead, I set all my AMX devices (including MVPs) to DHCP. I register my MAC addresses with the IT dept. When the AMX device requests an IP from the DHCP server, the server looks up a table, matches my MAC to an entry in the table, and gives me an IP address. In most default DHCP servers, they reserve a "pool" of IPs, so you could get anything out of that pool. In our setup, since there is a match for my MAC, I am always served the same IP - the DHCP server reserves it for me. This allows the IT dept to manage devices on their network better, since their DHCP servers can probably prevent duplicate IPs, etc. At the very least, it removes the issue of end-users upsetting others.

    Once I've got a "static" IP set up, I then obtain a DNS entry (from the IT dept) for my AMX gear. The DNS server essentially does a map between an IP address and hostname-domain pair. I'm not sure how critical it is, but it makes sense to me to make the hosname on your NetLinx (or Modero) the same as the first part of your DNS entry.

    It works like a charm, once both you and the IT dept know what is going on. The only exception to this is the MVPs. They seem to need rebooting for networking changes to take effect, but the GUI does not indicate this. Quite misleading, and hopefully this will be fixed in a later firmware revision. To AMX - I'd rather this be dynamic release/renew rather than a reboot, if at all possible.

    Another issues that can occur is if someone unpatches your NetLinx from the router, and patches it into a different port on the router. In our setup, you are very likely to end up on a different subnet, which throws the whole DNS/IP resolution. I believe that our DHCP servers only look on their local subnet (255.255.255.*) before dispatching an IP. As such, I keep a table of all my AMX systems, their MACs, DNS entries and IP addresses. It helps when changes (deliberate or otherwise) are made by the IT dept.

    I don't know if this is helpful to anyone or not. Hopefully someone will find my comments useful.

    Yours,
    Roger McLean
    Swinburne University
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    SensivaSensiva Posts: 211
    Another Queue of questions

    Well... your comments gives me another 10s of questions, which leads me to do a complete detailed reading about networks... Thank you :)

    The point you want to say is Leasing IPs for specific MACs.... fine...

    What if they have changed their IP ranges... or anything else that makes this lease give another completely different IP..... I should visit the site and do some configs....... that's why I want to refer to the system devices by hostnames whatever its IP Address is.

    I want to
    IP_CLIENT_OPEN (dvAVSWITCH.PORT, KNOXSWITCHER, 3040, TCPIP)

    rather than
    IP_CLIENT_OPEN (dvAVSWITCH.PORT, 192.168.20.35, 3040, TCPIP)

    Thank You!
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    annuelloannuello Posts: 294
    I guess it would be dependent on the DHCP & DNS servers being able to talk to each other. If they make changes on the DHCP server which effects entries in the DNS server map (and your IP/RS232 converter), they should really be responsible for updating their DNS server as well. It may be possible to synchronise the two, depending on what systems they are using.

    However, the only real solution is for the IT dept to be aware of what your system requires to work. If they make changes that break your system, then they should really take the responsibility for it. They provide the IT infrastructure/service. It is really up to them to decide how they want to look after your system - either by giving you "static" IPs, synchronising their DHCP & DNS servers, or set asside some special IP ranges for you to use.

    From the AMX side of things, you can put the hostname/domain into the IP_CLIENT_OPEN() function, rather than a static IP. That should work fine. If you look at the AMX master's "Network Addresses" using Netlinx Studio, you will see on the right hand side what DNS server the AMX contacts to resolve addresses.

    I'm not sure if you already do this or not, but it may be worth while polling the IP/RS232 converter (or the Knox switcher plugged into it) just to monitor the connection. When it is broken, email yourself of if appropriate, the IT dept. Such code should be pretty reliable, since you don't want false alarms.

    Roger McLean
    Swinburne University
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    SensivaSensiva Posts: 211
    Ok.... I Got it

    Thanks You very much.. :)
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