Airport Express static IP configuration

Posted:
in Genius Bar edited June 2014

My DSL provider, who placed at home a modem with 4 ethernet ports, does not have DHCP and gave me the following details: IP, Subnet Mask, Gateway (I’m presuming this is the Router address to be internet in Airport Express), DNS and alternate DNS. I configured it as a Static IP, and initially AirPort Express suggested that I put the router in “Bridge Mode” and pointed me to how I can change it. Now the router indicted green but Internet was still amber. Following all this, when I tried connecting using my MacBook, I get the message that it has a “self-assigned IP and cannot connect to the internet”. I don’t know what to do to make it work.

 

I configured the same settings for the Ethernet adapter on my MacBook and I’m able to connect to the internet. I don’t know if this is helpful but thought I’d put all the information I have on the forum.

Comments

  • Reply 1 of 3
    MarvinMarvin Posts: 14,182moderator
    It doesn't make much sense to have a modem with multiple ethernet ports without the ability to use DHCP as each machine connected needs to get an IP. What's the model of the modem? DHCP may just be disabled.

    The modem should have a web-based admin page where you can configure settings.

    If you absolutely can't get DHCP running on the modem, the Airport can't be in bridge mode, it needs to be set to act as a DHCP server to be able to assign an IP to devices connecting to it.
  • Reply 2 of 3

    Thanks for your reply. I switched out of Bridged mode into DHCP and NAT. This raised a Double NAT error from Airport. I broadly understood the logic that Airport has to act as the DHCP server and so I switched to DHCP only. This did the trick and now I'm connected to the internet! But, now it lets me access internet on only one device at a time.

     

    See, when I log in for the first time, I've to enter a username and password to log into the ISP's gateway - much like in a hotel. But, the ISP guaranteed to me that I'd have to do it only once if I've a wireless router as entering it once on a device will keep the gateway open for other devices. Now, once I've logged into my MacBook I lose internet on my iPhone. Could this be solved somehow?

  • Reply 3 of 3
    MarvinMarvin Posts: 14,182moderator
    Thanks for your reply. I switched out of Bridged mode into DHCP and NAT. This raised a Double NAT error from Airport. I broadly understood the logic that Airport has to act as the DHCP server and so I switched to DHCP only. This did the trick and now I'm connected to the internet! But, now it lets me access internet on only one device at a time.

    See, when I log in for the first time, I've to enter a username and password to log into the ISP's gateway - much like in a hotel. But, the ISP guaranteed to me that I'd have to do it only once if I've a wireless router as entering it once on a device will keep the gateway open for other devices. Now, once I've logged into my MacBook I lose internet on my iPhone. Could this be solved somehow?

    If you get a NAT error, the modem must be providing this. DHCP auto assigns addresses, NAT converts a single external IP into local ones. You need both.

    What bridge mode does is allows the modem to do the address translation but without DHCP, it can't assign the addresses automatically.

    I'd say try enabling DHCP and NAT but change your IP range on the Airport:

    http://support.apple.com/kb/PH5140

    "Choose a range of IP addresses from the DHCP Range pop-up menu. Choose 10.0, 172.16, or 192.168, and then enter a beginning and ending address in the beginning and ending fields, depending on which addresses you want the device to provide."

    The common one is 192.168 so if that's selected, it would conflict with the modem range. If you change this to one of the others, it shouldn't conflict, it might still warn about a double NAT but it should be ok.
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