VPN Client does not get IP from bridged network

[aramp]

Hi everybody,

Let me describe my setup in few words. I have a SoftEther VPN running on the VPS (CentOS 6) with real IP address. I'll refer to it as a "server". At home there is an OpenWRT (Chaos Calmer) router that have SoftEther Bridge installed. The bridge is attached to the local hardware bridge along with all internal interfaces (ethernet and wifi) and is connected to the virtual hub at the server. Because my provider at home does not let me have real IP address, that's the way for me to get into my home network from Internet. I know there is also vpnazure, but it's not available on all my devices. I want to have a universal solution.

Now, I am trying to connect to the same virtual hub on the server from my Mac OS computer through L2TP, but it can't get an internal IP address from OpenWRT home router. I have tried to run tcpdump on the ports 67 and 68 on the home network. It turned out that the connecting computer sends "DNSDISCOVER" broadcasts on the LAN segment, and I can see them on the router and on other computers attached to the router, but this broadcasts are never answered. Here is one example:

00:54:31.169071 IP (tos 0x0, ttl 128, id 48565, offset 0, flags [none], proto UDP (17), length 314)
0.0.0.0.bootpc > 255.255.255.255.bootps: [udp sum ok] BOOTP/DHCP, Request from ca:60:4a:1a:5a:0a (oui Unknown), length 286, xid 0xc515b3ec, Flags [none] (0x0000)
Client-Ethernet-Address ca:60:4a:1a:5a:0a (oui Unknown)
Vendor-rfc1048 Extensions
Magic Cookie 0x63825363
DHCP-Message Option 53, length 1: Discover
Client-ID Option 61, length 7: ether ca:60:4a:1a:5a:0a
Hostname Option 12, length 7: "airaram"
Vendor-Class Option 60, length 8: "MSFT 5.0"
Parameter-Request Option 55, length 12:
Subnet-Mask, Domain-Name, Default-Gateway, Domain-Name-Server
Netbios-Name-Server, Netbios-Node, Netbios-Scope, Router-Discovery
Static-Route, Classless-Static-Route, Classless-Static-Route-Microsoft, Vendor-Option

The server itself works well, I have set up another virtual hub at the same server to connect through VPS to Internet, and there are no issues at all, its fast and stable. I have tried to use fixed address on the client, but it then sends DHCPINFORM broadcasts that are not answered either. This also leads to the client failing to connect.

Where should I look for the reason?

[aramp]

As there is no reply, I will post my solution. I have basically moved back to OpenVPN, installed the bridge connection between home router and VPN server on VPS, and everything worked very smoothly without any additional effort. So the problem is somewhere in the way SoftEther implemented TAP interface: it does not go well with openwrt kernel network bridge.

[mkaand]

aramp wrote:
> As there is no reply, I will post my solution. I have basically moved back
> to OpenVPN, installed the bridge connection between home router and VPN
> server on VPS, and everything worked very smoothly without any additional
> effort. So the problem is somewhere in the way SoftEther implemented TAP
> interface: it does not go well with openwrt kernel network bridge.

I don't know your are still here or not but I successfully implement SoftEther VPN on my DDWRT router. I wrote a tutorial please read from begin to end. Maybe it helps. I had same issue but I fixed it.

http://www.dd-wrt.com/phpBB2/viewtopic. ... highlight=

[aramp]

mkaand wrote:
> I don't know your are still here or not but I successfully implement SoftEther VPN on
> my DDWRT router. I wrote a tutorial please read from begin to end. Maybe it helps. I
> had same issue but I fixed it.
>
> http://www.dd-wrt.com/phpBB2/viewtopic. ... highlight=

Thank you! Your blog post will definitely help other people. As to me, I will stay with OpenVPN solution for now. It works well, and there is no need to have it replaced with Sofethrr