Internet connection hibernation!?

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lamthai

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My MAC using OS X 10.6.7 is being connected to a switch that also serves another PC running Windows 7. The switch is being connected to the Internet via a modem. The IP of the PC is 198.162.1.102; the MAC has two IPs - 198.152.1.100 for Ethernet and 198.162.1.101 for the wireless (Airport). The switch's IP address is 198.162.1.1.

Once the MAC has been left alone for a while, both active Firefox and Safari browsers drop their Internet communication! And I cannot browse any thing anymore. The only way that I can re-establish their connections is to renew DHCP lease. If I don't do this, the Ethernet diagnostic mode activated via the 'Assis me...' button would continue to indicate that I have no Internet connection (i.e., shown w/ the red light instead of the green one).

So what must I do to correct this problem? Please help.

Thanks
Lam Thai
 
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This is strange. First open System Preferences->Energy Saver and make sure you don't have something check-marked. Then go to System Preferences-Network and at the top of the Network pane use the drop-down to create a new Location (calling it whatever you want - I call mine 'Home'). Then after creating the new Location look near the bottom right of the Network pane and click on the 'Apply' button to save this new Location. See if this fixes your problem.
 
Thank you for your reply but both of your suggestions did not help. In any event, the IP numbers that I gave earlier were all wrong; they should have started with 192.168 prefix.

By the way, I should provide a bit more relevant information. WhenI connect my MacBook directly to the modem, I experience no problem. But because the modem has only one port, I bought a 4-port wireless router (switch) TP-LINK TL-WR740N so both of my computers - the MacBook and a DELL - can have access to the Internet. Once my Mac is hooked up to the router, the problem starts to occur.

Yesterday I thought the problem only occurs when my Mac goes idle; however, this morning its Internet connection dropped while I was surfing the Internet (and as I shared in the original thread, all I need is to renew the machine's DHCP lease, I could re-establish the connection). I thought the problem was due to the router's short setting of DHCP lease time of 120 minutes. I increased the parameter to 1200 minutes but that did not fix the problem.

I went ahead and change the router and used another one, which is a CNET XWR-854. Well the same problem happened! Therefore, I can only guess that the problem must be OS-X related because my DELL works beautifully no matter how I configure my network.

Please note that when the problem occurs, using Terminal App, I can only ping 192.168.1.1 but not other IP addresses. In other words, my Mac can talk to the router but has no Internet connection.

Thanks and best regards,
Lam
 
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Open System Preferences->Network and click on the 'Advanced'. Then in the Advanced window click on the DNS and see if you are getting DNS.
 
OK. A switch and a router are different things. A router assigns a different IP address to each device connected to it. A switch requires a router upstream to assign different IP addresses for each device. Otherwise, all devices connected to the switch have the same IP address. I know nothing about your modem. Some modems have built-in routers. In this case, a switch is sufficient. If your modem does not have a built-in router, then a switch is insufficient if you have a Mac in your network.

As a general proposition, you cannot switch between a Mac and other device with the same IP address. If you want to use your Mac after accessing the Internet from your PC, then you must reset the modem. If you have a router [wired or wireless], however, the router assigns each connected device its own IP address. You may access the Internet from all of your networkable devices simultaneously.
 
What is the DHCP lease time set to on the router? One hour? One day? One week?

If the DHCP lease time is set to something extremely short, then it's possible that the computers, when asleep, lose their DHCP lease and are unable to renew it once awaking.

Log into your router (or DHCP server) and check the DHCP lease time.
 
MisterMe said:
OK. A switch and a router are different things. A router assigns a different IP address to each device connected to it. A switch requires a router upstream to assign different IP addresses for each device. Otherwise, all devices connected to the switch have the same IP address. I know nothing about your modem. Some modems have built-in routers. In this case, a switch is sufficient. If your modem does not have a built-in router, then a switch is insufficient if you have a Mac in your network.

As a general proposition, you cannot switch between a Mac and other device with the same IP address. If you want to use your Mac after accessing the Internet from your PC, then you must reset the modem. If you have a router [wired or wireless], however, the router assigns each connected device its own IP address. You may access the Internet from all of your networkable devices simultaneously.
Click to expand...

Thank you for the note. As I stated in my original post, when both of my Mac and DELL are running, I can see that the IP of my MacBook for the connection through a LAN port of the switch is 192.168.1.100; its Airport's IP address is 192.168.1.101; and h IP for DELL is 192.168.1.102. These addresses are assigned automatically. Therefore, based on what you shared with me, I should not need to renew my DHCP lease.

It's really weird even when my DHCP lease time is set to 1200 minutes, the Internet connection keeps dropping within 10 minutes if I use either LAN or Airport connection.

Thanks for your suggestion.
 
lamthai said:
Thank you for the note. As I stated in my original post, when both of my Mac and DELL are running, I can see that the IP of my MacBook for the connection through a LAN port of the switch is 192.168.1.100; its Airport's IP address is 192.168.1.101; and h IP for DELL is 192.168.1.102. These addresses are assigned automatically. Therefore, based on what you shared with me, I should not need to renew my DHCP lease.

It's really weird even when my DHCP lease time is set to 1200 minutes, the Internet connection keeps dropping within 10 minutes if I use either LAN or Airport connection.

Thanks for your suggestion.
Click to expand...
It is not at all clear what your network setup looks like. The fact that your devices have different IP addresses is all to the good. However, it does not mean that you are setup properly. A few questions:
  • What do have connected to the Ethernet port of your modem?
  • What is the WAN port of your Airport connected to?
  • What are the LAN ports of your Airport connected to, if anything?
  • What connects wirelessly to your Airport?
  • Which model Airport do you have?
  • Is the Airport your only router?
  • What is the WAN port of your switch connected to?
  • What are the LAN ports of your switch connected to?
This is how your network should be setup:
  1. Cable goes from wall outlet to input of splitter. One output of cable splitter goes to cable modem.
  2. Ethernet connects cable modem to WAN port of Airport.
  3. Ethernet connects WAN port of switch to LAN port of Airport.
  4. Ethernet connects wired devices to LAN port of switch.
  5. Devices with wireless connection connect wirelessly to Airport.
You have many more IP addresses than devices to assign them to. DHCP lease times should not be a concern.
 
MisterMe said:
It is not at all clear what your network setup looks like. The fact that your devices have different IP addresses is all to the good. However, it does not mean that you are setup properly. A few questions:
  • What do have connected to the Ethernet port of your modem?
  • What is the WAN port of your Airport connected to?
  • What are the LAN ports of your Airport connected to, if anything?
  • What connects wirelessly to your Airport?
  • Which model Airport do you have?
  • Is the Airport your only router?
  • What is the WAN port of your switch connected to?
  • What are the LAN ports of your switch connected to?
This is how your network should be setup:
  1. Cable goes from wall outlet to input of splitter. One output of cable splitter goes to cable modem.
  2. Ethernet connects cable modem to WAN port of Airport.
  3. Ethernet connects WAN port of switch to LAN port of Airport.
  4. Ethernet connects wired devices to LAN port of switch.
  5. Devices with wireless connection connect wirelessly to Airport.
You have many more IP addresses than devices to assign them to. DHCP lease times should not be a concern.
Click to expand...

Thank you for your suggestions. Here is my network configuration:

1st tier: A 1-port router/modem KRRUN connected to a cable from ISP - DHCP lease time = 1200; IP = 192.168.1.1

2nd tier: TP-LINK WR740N or CNET CWR-854 4-port wireless router (DHCP disabled). This has 1 WAN port and 4 LAN ports. It's LAN port #1 is connected to the OUT port of the modem in tier #1.

3rd tier: Two computers:
- a MacBook connected to the router's LAN port #2 and has an IP address of 192.168.1.100 - and its wireless IP address is 192.168.1.101.
- a DELL connected to the router's LAN port #3 and its IP address is 192.168.1.102.

Please note that I did try to connect the output of the first tier to the WAN port of the second tier but both my Mac and DELL would not connect to the Internet. With the configuration I shared with you, at least my DELL behaves reliably.

Anyway, if I have to renew DHCP lease time for my Mac, why doesn't my DELL act abnormally? If the problem is with the 2nd tier, why changing to another router does not fix the problem...?

Perhaps I should replace my Mac with an ACER laptop to see if the problem would occur. I know there is no conflict between my Mac and my DELL because w/o the DELL in the loop, my Mac still behaves erratically unless I promote it to the 2nd tier. But in that case, I cannot hook the DELL to the Internet because it has no wireless support.
 
I finally got my network to work correctly. Apparently, my Mac is too sensitive and is not as tolerable as the DELL of mine. Windows 7 seems to adjust along with the Dynamic IP settings of my 2nd tier router; but OS X could not keep up with the constant update from the modem KRRUN which is connected directly to the modem cable set up & controlled by my ISP.

So the solution to prevent the Mac dropping off the Internet connection is as follows:

#1. I re-connected the 1st tier's OUT port to the WAN port of the 2nd tier.
#2. I changed the IP address of the 2nd tier router to 192.168.2.1 to differentiate it from the modem, which uses 192.168.1.1
#3. I set my WAN operation to Static mode (I ignored the only two choices given by the router's instruction - Dynamic IP or PPPoE).
#4. I copied the WAN parameters of my 1st tier modem to the 2nd tier router.
#5. I enabled the 2nd tier router's DHCP server and changed its Gateway IP to 192.168.2.1

With the new change I've just described, my network now works reliably.

I would like to thank you all for visiting the forum, reading my post and especially sharing your knowledge with me.

All the best,
Lam
 
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