Weird GS1915 series default

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mMontana
mMontana Posts: 1,337  Guru Member
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As stated by manual: management address is
(still the useless limitation to not user-allow copy from PDF manuals… worked around without using Adobe Reader).
http://setup.zyxel
or
http://DHCP-assigned IP
or
http://192.168.1.1

The latter is the same default address of every Zyxel router and firewall. It seems a bit problematic if there's already another device on the same IP address. If i put a new GS1915 into a network with the gateway configured on 192.168.1.1…. will it block any external connection until I reconfigure management IP?

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  • PeterUK
    PeterUK Posts: 2,856  Guru Member
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    What I do is hook it up to a PC to change the management address IP before hooking it up to the network

  • mMontana
    mMontana Posts: 1,337  Guru Member
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    I know some paths for avoid the problem.

    But the question
    If i put a new GS1915 into a network with the gateway configured on 192.168.1.1…. will it block any external connection until I reconfigure management IP?
    still stands. I would love to know what happens if… without having to buy it and test it.

  • PeterUK
    PeterUK Posts: 2,856  Guru Member
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    OR you can simply not ask the question :)

    If there is a DHCP server that the switch is connected too it will get some IP

  • mMontana
    mMontana Posts: 1,337  Guru Member
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    Not asking the question won't lead to this topic.

    Circular logic sometimes goes to shortcircuit.

  • PeterUK
    PeterUK Posts: 2,856  Guru Member
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    edited June 2023
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    Ok so lets say you have a unmanaged switch to a Zywall router 192.168.1.1 without DHCP devices need to find the gateway so they must broadcast ARP then after they can do one of two thing to keep checking the gateway broadcast or unicast.

    So you add this GS1915 it can't get a IP by DHCP so its 192.168.1.1 your PC doing unicast ARP to 192.168.1.1 will still go to Zywall router so what happens if you ARP -d on PC you broadcast ARP for 192.168.1.1 to which you have a race between the GS1915 and Zywall router if the PC pick one you will go to one.

  • Zyxel_Melen
    Zyxel_Melen Posts: 1,716  Zyxel Employee
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    edited June 2023
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    Hi @mMontana,

    May I know what the external connection means? Did you create a NAT rule to access 192.168.1.1?

    In addition, the GS1915 will ask for DHCP IP address by default. If the gateway/firewall enables DHCP server, GS1915 will change to the DHCP IP address it gets.

    Zyxel Melen

  • Zyxel_Melen
    Zyxel_Melen Posts: 1,716  Zyxel Employee
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    In addition, the GS1915 uses DHCP as the first priority for the management IP address.

    Zyxel Melen

  • mMontana
    mMontana Posts: 1,337  Guru Member
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    I'll try to rephrase it, @Zyxel_Melen

    I buy a GS1915 series switch. I use it into a 192.168.1.0/24 network without DHCP server active. In this network 192.168.1.1 is the main gateway. I connect ALL the devices to this switch.
    What will happen? Will it block the connection to the gateway?

    I know that "block" is improper, but as a matter of fact, if your proxy device (switch is the closest device to wired device, AP for wireless) says "i'm 192.168.1.1" it should not forward any packet to the "actual"/former 192.168.1.1 device which is the gateway…

  • PeterUK
    PeterUK Posts: 2,856  Guru Member
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    I buy a GS1915 series switch. I use it into a 192.168.1.0/24 network without DHCP server active. In this network 192.168.1.1 is the main gateway. I connect ALL the devices to this switch.
    What will happen? Will it block the connection to the gateway?

    Like I said their be a race😉

  • mMontana
    mMontana Posts: 1,337  Guru Member
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    edited June 2023
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    As I wrote before, i don't wanna know if trying. Therefore I'm asking.