Windows OpenVPN Client with OvpnServer RB1000 v4.3

manuelritter · Wed Dec 02, 2009 2:28 pm

Hello Community,

i have RB1000 with ROS 4.3 running a OpenPVN Server. There are connected at least 20 Mikrotik Routers with User and Password auth and have no Problems.
But if I connect a Windows Client, i got an Error on Client side.

ERROR: There is a clash between the --ifconfig local address and the internal DHCP server address -- both are set to xxx.xxx.xxx.xxx -- please use the --ip-win32 dynamic option to choose a different free address from the --ifconfig subnet for the internal DHCP server

Any idea how to resolve?

OVPN Server Config on RB1000 ROS 4.3

                     enabled: yes
                        port: xxxxx
                        mode: ethernet
                     netmask: 32
                 mac-address: XX:XX:XX:XX:XX:XX
                     max-mtu: 1400
           keepalive-timeout: 60
             default-profile: default
                 certificate: cert1
  require-client-certificate: no
                        auth: md5
                      cipher: aes128

Windows Client Config:

proto tcp-client
remote xxx.xxx.xxx.xxx xxxxx
dev tap
ca ca.crt
nobind
persist-key
tls-client
ping 10
verb 3
cipher AES-128-CBC
auth MD5
pull
ip-win32 dynamic

Greetings Manuel Ritter

Mon Dec 07, 2009 1:39 pm

DHCP assigned address is the same as OVPN assigned address, this is not valid configuration. OVPN assigned address must be from different IP pool.

manuelritter · Tue Feb 09, 2010 11:29 am

What should i change and where ?
Sorry, but i dont know what to do, which dhcp pool you mean?
The default profile has no ip pool and the client login has one static ip.

Greetings
Manuel Ritter

MartinFromDE · Fri Dec 22, 2017 1:41 am

Even if this thread is several years old. I had the same error message and found a solution for me.

Since WinXP-Client (OpenVPN 2.1.x; 2.0.9) worked, Win10 (2.3.14) gave me the error message.

My pool was too large. There seems to be an (virtual) DHCP-Server with the ip .254. My pool was 192.168.21.10-192.168.21.254 .

After reducing the range (in my case to 192.168.21.10-192.168.21.20; this is enough for 1 Client

) the error message disappeared and OpenVPN works like a charm

Now I can see that there is the DHCP-Server on 192.168.21.254 ... before it brake too early and did not gave me the IP of the DHCP-Server ...

Maybe it will help anybody ...

RouterOS 6.38.3
hap lite

maikel · Fri Feb 23, 2018 12:03 pm

Even if this thread is several years old. I had the same error message and found a solution for me.

Since WinXP-Client (OpenVPN 2.1.x; 2.0.9) worked, Win10 (2.3.14) gave me the error message.

My pool was too large. There seems to be an (virtual) DHCP-Server with the ip .254. My pool was 192.168.21.10-192.168.21.254 .

After reducing the range (in my case to 192.168.21.10-192.168.21.20; this is enough for 1 Client ) the error message disappeared and OpenVPN works like a charm

Now I can see that there is the DHCP-Server on 192.168.21.254 ... before it brake too early and did not gave me the IP of the DHCP-Server ...

Maybe it will help anybody ...

RouterOS 6.38.3
hap lite

Thanks a lot!

rbuserdl · Wed Oct 14, 2020 10:37 pm

I just see again the client logs and realice that it pointed to 192.168.16.254, it seems that although the profile is configured with 192.168.16.1as local address, there is a kind of conflict with the last IP of the pool
I just changed my pool from [192.168.16.250 - 192.168.16.254] to [192.168.16.241 - 192.168.16.250] and started to work
Weird issue.

Thanks
Regards
Damián

onion83 · Sun May 30, 2021 1:17 pm

I just see again the client logs and realice that it pointed to 192.168.16.254, it seems that although the profile is configured with 192.168.16.1as local address, there is a kind of conflict with the last IP of the pool
I just changed my pool from [192.168.16.250 - 192.168.16.254] to [192.168.16.241 - 192.168.16.250] and started to work
Weird issue.

Thanks
Regards
Damián

👍 👍 👍

Yes ,When reduce pool size , it works.

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