# PPPoE and DHCP coexists!?



## suntannedboy (Feb 16, 2009)

Hi, every expert
I have a Xserve (Leopard Server) that can give DHCP to my Macs but at the same time, I also use a PPPoE modem that gives 6 dynamic IPs + 1 static IP. So I wonder if I could use DHCP and PPPoE at the same time?

As far as I test, DHCP is way slower in terms of internet connectivity than the PPPoE direct connection. But at the same time, if I don't use DHCP, I cannot use LDAP.

I don't want to sacrifice my internet speed. So is there anyway to use PPPoE while keep DHCP available  just for LDAP purpose?

I also don't want to use NAT also because of the slower internet connectivity. But not using NAT means I cannot use Gateway Setup Assistant, which also means I cannot setup my en0 and en1 interfaces correctly. Help!!!

Thanks, experts~


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## ElDiabloConCaca (Feb 16, 2009)

I think you're confused somewhere along the line.  PPPoE and DHCP can be used at the same time on different network interfaces.  We need more information about your setup in order to continue.

I'm guessing that you've got an XServe connected to a DSL (or some type) of modem that uses PPPoE to connect to the internet, correct?  You then have the XServe attached to an ethernet switch/hub, and other computers connected to the switch/hub, too, right?  And the XServe is running DHCP to assign IP addresses to the "client" machines?

If that's not right, please explain your network setup in greater detail.


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## suntannedboy (Feb 17, 2009)

Okay, let me quickly give you a sketch here.

I have 6 dynamic IPs and 1 static IP provided by my ISP.

My modem is connected to a D-link switch on the 1F. The switch has a link to the 2F where my Xserve (WAN en0) is located. I have to put it on the 2F.

All my iMacs and PCs are on the 1F, also connected to the D-link switch.

Then the Xserve's en1 for LAN is connected to a cable linked to an ASUS switch located on 1F, which is then linked to the D-link switch.

I have to make a big circle because of the office design; I had no choice.

If it wasn't for the LDAP purpose, I wouldn't use DHCP because using it as internet share for my iMacs is very slow. Normally, I directly use PPPoE for my iMacs. They are just faster than either NAT or DHCP.

Also, for right now, I don't see any reason to use NAT because I have enough IPs. But I am forced to use it because I want to use NAT's Gateway Setup ASsistant to setup my network en0 and en1 correctly.

One more thing, my modem can act as a DHCP server but I don't want to do that. I want to use my Xserve as a DHCP server. The modem has a default IP (192.168.1.1) But you know when I use the Gateway Setup Assistant, it automatically put Xserve's en1 as 192.168.1.1. The next thing you know is IP Address clashes.

Let me know if you need more info.
Thank you very much.


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## suntannedboy (Feb 17, 2009)

okay, let me update my ethernet interfaces, correct me if I setup wrong.

Xserve Leopard

Ethernet 1
Configure Manually
IP Address: 10.xx.xxx.xxx (I put my static IP provided by my ISP here, am I right?)
Subnet Mask: 255.255.255.0
Router 192.168.1.1 (I used my modem's default IP, am I right here?)

Ethernet 2
Using DHCP with manual address
IP Address: 192.168.1.2
Subnet Mask: 255.255.255.0
Router: blank

I also use PPPoE.

Now the question arises if I want to setup my webpage: should I leave my PPPoE connected to the internet at all time? Or is PPPoE just for myself to connect to the internet and others can still link to my webpage through interface en0 even when I turned off PPPoE?

Thank you guys.


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