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RRAS not giving DHCP addresses via PPTP VPN

Hi all,

I've got a SBS 2003 server that's started giving me problems recently. I can connect via PPTP VPN but always get a self-assigned address (169.x.x.x) until I restart RRAS from within the RRAS console. This started happening 1-2 weeks ago.

A few quick googles didn't yield much but did help me realise that something strange is going on - two processes are running on port 67 (DHCP) on the server (see below).

After I restart RRAS, the SVCHOST PID changes but still is running on port 67 concurrently with DHCP. Despite two processes listening on port 67, RRAS now gives PPTP clients a valid IP (10.x.x.x)

Any ideas on the cause and fix?

============
netstat output:
============
 
Active Connections
 
  Proto  Local Address          Foreign Address        State           PID
  UDP    10.0.0.8:67            *:*                                    1612
  UDP    10.0.0.8:67            *:*                                    7272
 
 
============
Tasklist output:
============
 
Image Name                     PID Services                                    
========================= ======== ============================================
 
svchost.exe                   1612 AeLookupSvc, BITS, Browser, CryptSvc,       
                                   dmserver, EventSystem, helpsvc,             
                                   lanmanserver, lanmanworkstation, Messenger, 
                                   Netman, Nla, RasMan, RemoteAccess,          
                                   Schedule, seclogon, SENS, ShellHWDetection, 
                                   winmgmt, wuauserv

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Netman66

Are you running WDS on this server also?

You may want to check DHCP leases next time you encounter this problem - see if the scope is exhausted or there are 10 RRAS leases already.

Normally, RRAS reserves 10 IPs at a time from DHCP for use with the clients that RAS in, when that pool gets near it's capacity, then RRAS will request another block of 10 IPs. I think you may have a pool exhaustion happening.

Vires_PtyLtd

ASKER

After a month, the problem finally came back so I could look at things while they were messed up.

It only seems to happen after the server restarts.

A few other symptoms:
* In DHCP, there are no RAS reservations - whether things are working or not. This is the first SBS server I've seen with a DHCP Relay Agent configuration. (In RRAS, under IP routing there is General, Static Routing, and DHCP routing entries).

* In RRAS, the Internal interface is Up but has a 169.*.*.* self-assigned address. After restarting RRAS, it correctly has a 10.0.*.* address.

It looks as though RRAS tries to reserve addresses and can't, then falls back to a 169.*.*.* IP. Others have suggested changing the boot order of the services (to make sure DHCP starts up first - how do I do this?), checking if a rogue DHCP server is interfering (none as far as I can see), and if the DHCP server is trusted (it is Active Dir authorised).

Any suggestions?

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Netman66

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Vires_PtyLtd

ASKER

Thanks for the help - there doesn't appear to be a way to add dependencies via services.msc but I found the microsoft documentation on adding dependencies via the registry which worked.

Vires_PtyLtd

ASKER

I was able to add a dependency by following the microsoft instructions available here:

http://support.microsoft.com/kb/193888

Instructions:

Backup and open the registry
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\<Service name>
Add a key of type REG_MULTI_SZ named DependOnService (if it doesn't exist already)
Add the service dependcies, ONE per line

Note: To wait for the DHCP server, add "DHCPServer" not "DHCP" (this is the client)

Changes seem to be instantly reflected in services.msc

Netman66

Perfect! Nice work.

Thanks!
NM