Please help: Network setup

[stoavio]

Hey all,

Ok, here's my quandry. I have a network powered by a LinkSys BEFW11S4 router connected to a Comcast Broadband internet connection. I have 4 computers and a xbox all connected to the network. My problem is that the router is configured to assign IP addresses dynamically (so of course each computer's IP address will be ever changing) ergo port forwarding will not function properly. Applications like Remote Desktop, P2P apps, etc., that require certain ports to remain open won't operate properly if the port was opened on 192.168.1.1 and the router has since reassigned the IP to 192.168.1.2 after either a power cycle or computer reboot.

So, here is my question. I'd like my primary computer (which is my Powerbook) to have a static IP address so that port forwarding works correctly. Now, I know that when you give one computer a static IP, every other computer connected to the same network also needs a static IP. I really want to avoid doing this. Is there anyway, with the configuration I described above, to create some kind of rule that tells my router "Hey, don't give away the IP address 192.168.1.1 because its reserved for [Mason's Powerbook]" so that the computer knows its free to dole out every other address but that one to computers on the network?

I really don't want to go out and purchase a new router. I'd just like to make my current setup work.

 

[jsw]

On every Linksys router I've had, there's been a way to say where to start the DNS addresses and how many to allow. If that's the case with yours, just assign the PB an IP outside that range but within the submask area.

For example, if it starts at 192.168.1.1 and allows 50, assign the PB to 192.168.1.51.

And/or limit the number of DNS addresses to a smaller number.

And/or start them higher (i.e., 192.168.1.100 or whatnot).

 

[stoavio]

@jsw: Thanks for the tip. It seems logical but I'm not sure how to set it up. I've taken a screenshot of my router's web based utility main page. Do you see where I can set that up here?

 

[Le Big Mac]

@jsw: Thanks for the tip. It seems logical but I'm not sure how to set it up. I've taken a screenshot of my router's web based utility main page. Do you see where I can set that up here?

see where it says "start IP address range"? You have it to start at .16. In your network prefs (on system prefs.) set a fixed IP on your computer of 192.168.1.15 (or .14 or .13, etc.). You also have to copy the DNS entries. You then have a fixed IP for that computer, the rest will have DHCP.

 

[stoavio]

Thanks, I'll try that and see how it works.

Also, where do I get the DNS entries from to copy them? I ran the following command in Terminal and got this in return:

cat /etc/resolv.conf

domain hsd1.mi.comcast.net.
nameserver 68.87.77.130
nameserver 68.87.72.130

Are those two it?

 

[jsw]

Oh, it's much easier than that.

Just choose "Using DHCP with manual address" in the network settings - all you need to do then is enter the IP address, nothing else.

In your case, you'd enter 192.168.1.15, and you should then be all set.

 

[stoavio]

Awesome. But, isn't 192.168.1.15 the router's IP address?

I'll try it.

 

[x86]

Awesome. But, isn't 192.168.1.15 the router's IP address?

I'll try it.

I think it is. Try bumping your "Start IP Range" up by one to 17 and then set your computer to 192.168.1.16.

 

[nsutt22]

Oh, it's much easier than that.

Just choose "Using DHCP with manual address" in the network settings - all you need to do then is enter the IP address, nothing else.

In your case, you'd enter 192.168.1.15, and you should then be all set.

This will give your pbook the manual IP 192.168.1.15 or whatever u assign it however if the DHCP ip range is still including the .15 there is a chance if your pbook is not using that IP that another computer will grab .15 thus taking it away from your poor pbook when it tries to connect with the manual setting.

I am pretty sure at least.

 

[jsw]

This will give your pbook the manual IP 192.168.1.15 or whatever u assign it however if the DHCP ip range is still including the .15 there is a chance if your pbook is not using that IP that another computer will grab .15 thus taking it away from your poor pbook when it tries to connect with the manual setting.

I am pretty sure at least.

You're right, which is why it needs to be outside the range, and others are right in that I didn't see the router's IP. So 192.168.1.26 would be fine, if every other setting remained the same. Or you could just bump the starting address, as mentioned above.

So many ways to a happy solution.

 

[nsutt22]

I think it is. Try bumping your "Start IP Range" up by one to 17 and then set your computer to 192.168.1.16.

I believe this will work to. I am currently trying it on my Linksys router as well. Are u going to be doing outside port fowarding to this IP?

 

[stoavio]

Ok, I don't think that worked. Here is my router setup (main page again) and my System Preferences.

Router:

System Preferences:

I wasn't able to connect to the internet once I changed to 'Using DHCP with manual address'.

 

[jsw]

Possibly because another computer already has the '16' address because it was assigned by DHCP earlier.

Try 192.168.1.30 or something else which can't have been assigned already.

Edit: also, something's wrong because your subnet mask and router info should have been filled in shortly after you applied the change.

 

[nsutt22]

Yep, that will cause in issue cause your router is not sending out the IP 192.168.1.16

I am going to look more into this but a sneaky way right now would be to make your range 192.168.1.2 to 192.168.1.255 and then set your pbook manual IP to 192.168.1.222 The odds of 4 computers and an xbox getting assigned the IP 192.168.1.222 while your pbook is off is very very very low. Try that for the mean while.

 

[stoavio]

Ok, I've changed some things. Selecting 'Using DCHP with manual address' doesn't allow me to reconnect to the internet so I've selected 'Manually' from the drop down, entered 192.168.1.30 and then entered the nameserver returned by running the command: cat /etc/resolv.conf

I'm connected now. I wonder if this could create a conflict with the router and future IP assignments?

 

[nsutt22]

Ok, I've changed some things. Selecting 'Using DCHP with manual address' doesn't allow me to reconnect to the internet so I've selected 'Manually' from the drop down, entered 192.168.1.30 and then entered the nameserver returned by running the command: cat /etc/resolv.conf

I'm connected now. I wonder if this could create a conflict with the router and future IP assignments?

I would just make your range bigger and assign it to one farther down the range. Makes the odds of one of the 4 comps or xbox grabbing that speacil IP of yours.

 

[stoavio]

Edit: also, something's wrong because your subnet mask and router info should have been filled in shortly after you applied the change.

Yea, I kind of thought that too so I switched it to 'Manually' and it now looks like:

 

[jsw]

No - the router will never assign the '30' slot unless you change its current settings. I suspect the "Using DHCP with manual address" approach would have worked with '30' - it always does with me - but you found a way to get it to work, which is all that matters.

I'd assign it a location (like "Home") so you can switch away from it if you take the PB elsewhere - where DHCP is required (you could create another location - like "Away" - for that case).

 

[nsutt22]

No - the router will never assign the '30' slot unless you change its current settings. I suspect the "Using DHCP with manual address" approach would have worked with '30' - it always does with me - but you found a way to get it to work, which is all that matters.

I'd assign it a location (like "Home") so you can switch away from it if you take the PB elsewhere - where DHCP is required (you could create another location - like "Away" - for that case).

If the pbook is shut off the IP .30 is fair game don't forget.

 

[stoavio]

I would just make your range bigger and assign it to one farther down the range. Makes the odds of one of the 4 comps or xbox grabbing that speacil IP of yours.

But since I'm out of the DCHP range I don't ever need to worry about my new static IP (192.168.1.30) ever being selected and assigned to another computer by the router because it's out of range, right?

 

[nsutt22]

But since I'm out of the DCHP range I don't ever need to worry about my new static IP (192.168.1.30) ever being selected and assigned to another computer by the router because it's out of range, right?

I am sorry! I missed that it worked out of the range! You are totally good then. I am glad that worked cause I think i am going to try that. It deffinitly worked out of the range then?

 

[stoavio]

No - the router will never assign the '30' slot unless you change its current settings. I suspect the "Using DHCP with manual address" approach would have worked with '30' - it always does with me - but you found a way to get it to work, which is all that matters.

I'd assign it a location (like "Home") so you can switch away from it if you take the PB elsewhere - where DHCP is required (you could create another location - like "Away" - for that case).

@jsw: Thanks. I didn't know you could do that. That's a real good idea!

 

[stoavio]

I am sorry! I missed that it worked out of the range! You are totally good then. I am glad that worked cause I think i am going to try that. It deffinitly worked out of the range then?

It sure did. Just make sure to run that Terminal command to snag your nameservers (as you can see I only entered 1 of them because they both were the same) and you should be perfectly fine. Thank you for your help!

 

[jsw]

It deffinitly worked out of the range then?

Yes - see the router page - 192.168.1.117-192.168.1.26 are the only addresses it'll ever assign (as currently configured). And, of course, you could limit it more if you want.

 

[nsutt22]

It sure did. Just make sure to run that Terminal command to snag your nameservers (as you can see I only entered 1 of them because they both were the same) and you should be perfectly fine. Thank you for your help!

You lost me on the nameservers? What exactly is that for/do?