A few important network questions....

[Generix]

For anyone who dares attempt tackling my wordiness, thank you very much (in advance).

I have Earthlink ADSL (dynamic IP). My Earthlink modem is in bridge mode (no NAT or PPPoE enabled) and my router handles the PPPoE aspect. I only have one computer connected to my router. I believe I get a new IP address every 7 or 10 days from Earthlink, something like that. I was reading online somewhere that I should clone my mac address of my network card to my router because I have a dynamic IP. What will this help with? Should I do it?

Also, do I need to allow my router to act as a DHCP server? And if I allow it to act as a server and set my IP address to an address within the range it handles (192.168.1.x, normally I have it set to handle 100-149), should I turn off the DHCP service in windows? I've been advised to allow the router to act as a DHCP server but to set my IP address to something outside of its range. In this case, I was also advised to turn of the DHCP service in Windows.

I'm looking for the most solid connection I can squeeze out of my setup. I've been experiencing random disconnects at random times for no apparent reason. The only error in the event log that pertains to any of this is (although I haven't gotten it in about 12 hours so far):

Event Type: Warning
Event Source: dnscache
Event Category: None
Event ID: 11050
Date: 9/8/2004
Time: 11:22:20 PM
User: N/A
Computer: COMPUTER
Description:
The DNS Client service could not contact any DNS servers for a repeated number of attempts. For the next 30 seconds the DNS Client service will not use the network to avoid further network performance problems. It will resume its normal behavior after that. If this problem persists, verify your TCP/IP configuration, specifically check that you have a preferred (and possibly an alternate) DNS server configured. If the problem continues, verify network conditions to these DNS servers or contact your network administrator.
Data:
0000: b4 05 00 00 ´...


In the TCP/IP properties, I have the DNS servers set to the two static DNS servers shown on the router's status page. I have the gateway set to 192.168.1.1 (the router's IP), the subnet set to 255.255.255.0, and my IP address as 192.168.1.100.

My router's client lease time is currently one day (the maximum). Correct me if I'm wrong, but doesn't this setting mean that it refreshes my lease on the IP address (192.168.1.100) every day and therefore causes my connection to momentarily drop? Or perhaps it checks to see if I have been assigned a new IP from the ISP before assigning me a new one and dropping my connection? Or maybe I'm completely wrong and someone could let me know exactly how this setting affects me. From the looks of it it seems that I don't really need it seeing as how I only have one computer and get a new IP from Earthlink every 7-10 days.

OS: Windows 2K
router: Linksys BEFSR41

Basically, I'm wanting to know about:
1) mac address cloning with my router (if I should do it and what it will affect)
2) if I need DHCP (and how should it be configured...router, windows, neither, or both)
3) if I do need DHCP, how client lease time should be set up
4) any other general tips to establish a more solid network

Wow, you made it to the end. Thanks for ANY input whatsoever.

[igalan]

Wow, you're mixing many different things!

1. DHCP is a way to dynamically assing IP addresses, network masks, dns servers and gateways. A DHCP server assigns all these data to DHCP clients. So clients must not know anything about the network before connecting (you set everything to auto, and they get the correct configuration for TCP/IP). It's usually the best way to go. Typically you have a hardware router with DHCP enabled. Your Windows XP box uses the DHCP Client Service to retrieve and apply this TCP/IP data.
2. MAC addresses are unique identifiers of Ethernet devices. You can't use the same MAC address for two devices because in this scenario the hardware won't know to which device it should to send the data. Often ISP that install cable-modems check the MAC address of the computer that is plugged to the cable-modem; this way you can't change it (for instance, to connect a router that allows you to have several computers in the same network). To avoid this newer routers and firewalls with NAT routers allow you to change the MAC address. This way you can use the same MAC as the computer had to fool your ISP and connect several computers (you'll have to change the MAC address of the original computer too, remember that you can't have two devices with the same MAC address).
3. The DNS Client Service of Windows XP is a piece of software that caches DNS queries to improve performace. You can safely disable if you want. On Windows 2003 networks it improves the performance because Windows 2003 Server relies heavily on DNS instead of the older NetBIOS for name resolution.

I hope now everything makes some more sense .

[greffov]

I think igalan covers all.

Why haven't you enabled NAT on your modem? Or is your Linksys doing NAT? In case that is the point, your Linksys acts as router, and will probably offer you DHCP services.

[Generix]

Thanks for the replies.

Sorry, I was looking at a configuration page with mac address cloning for a cable modem (here).

With that in mind, I'm still slightly confused about DHCP. When it assigns IP addresses, is this referring to LAN IP addresses (192.168.1.x) or WAN IP addresses? Since my modem doesn't offer any configuration when NAT is enabled on it (Earthlink has took the liberty to disable configuration), I must turn off the NAT (and PPPoE) of the modem by putting it into bridge mode. I then allow the linksys router to handle the NAT and PPPoE. I think it would be easier to ask like this:

What would happen (in regards to network connectivity, uptime, errors, etc) if I.....
1)disabled DHCP in the router and the DHCP service in windows
2) disabled DHCP in windows but left it on in the router
3) disabled DHCP in the router but enabled DHCP in windows
4) enabled DHCP in the router and enabled DHCP in windows

From what I have managed to read, I have come to a small conclusion on what DHCP does. Please let me know what I have mixed up. DHCP will contact my ISP to see if I have a new WAN IP address and assign it to my LAN IP address. If the WAN IP address is the same (it only changes every 10 days), it does not need to reassign a new WAN IP to my LAN IP and therefore does not break my connection and I am a happy camper. If it detects that a new WAN IP address has been assigned to my computer, it will assign it to my LAN IP, temporarily dropping my connection. Therefore the client lease time would be how often it checks for a new WAN IP address. And then I guess I can also be sent a new WAN IP address by the ISP where the router will get the message to change without checking? I just don't want to have my connection dropped every time the client lease time expires.

[greffov]

a few things are getting confuxxled up now

I'll try to explain.

isp ==dhcp== modem ==== linksys ==dhcp== pc

so consider the schema above... you will notice two times dhcp in there.
The on the LEFT of the linksys is called WAN in the linksys. The part RIGHT is called LAN.

Now, you have a little bit tricky situation, this explains your confusion about mac addresses and stuff. Your linksys connects to the modem in order to get to your ISP. Your ISP has an DHCP server to supply your modem with an IP address. The MAC address cloning trick is only required when your ISP's DHCP server refuses to give your linksys an IP address. This is not the case for you, so you shouldn't bother about this. There is nothing what you can do about the left side of the linksys in the schema.

The right side, is where you can tweak things. The linksys acts to you as being your ISP. This means, the linksys also has a DHCP server built in to supply your PC(s) with an IP address if they ask for it.

Generally it's a good idea to let the linksys do it's work as DHCP server; it has a little linux kernel, so it works fine. It might not be as customisable as you like, but I don't think you want to 'patch' adresses to IP's. Don't worry about it. So stick to option 2. Enabling two DHCP servers (both linksys and a windwoes machine) is NOT a good idea.

So when I come back to your problems, I think that the linksys loses the connection with your ISP. Either the modem loses signal, or your ISP just disconnects you on purpose. They have to if they want to change your WAN IP address, there is nothing you can do about this but slamming your ISP I think.

You migth be on a 'black list' because of excessive downloading/uploading or something like that. Think about that before phoning them to ask them what's wrong with the line

[Generix]

Thank you, that helped very much. So I will turn off the DHCP service in windows and leave the DHCP enabled in the router. Under this situation, when the client lease time expires, my router will reassign my LAN IP (it doesn't even deal with the WAN IP) to my computer? Tell me if I'm wrong again.

[greffov]

sounds like you completely got the point

[igalan]

If you have Windows 2000 Professional, the DHCP service is a client service designed to retrieve DHCP data. don't shut it down. If you have Windows 2000 Server, you can have a DHCP Server set up, and that's a completely different story.

[greffov]

ohw, igalan has a good point, there is a difference between DHCP server and client... you need to have a client on your windows machine, (by default installed if you tick the automatically get an address), the DHCP server needs to be turned on on the Linksys.

[Generix]

I do have Windows 2000 Professional. I don't have the automatically obtain an IP address ticked (I manually set the IP, gateway, subnet, etc), so do I need the DHCP service running all the time? I guess I could just actually test it out heh. When I do an ipconfig /all, it says DHCP is not enabled for my NIC, if that makes any difference.

[greffov]

static is fine too, if it works, there is no need to change it.