Ziggo Internet, Juniper Firewalls and DHCP

At the house I have currently two ISP delivering broadband. Well, broadband isn't the correct word, since the the one of them is only a mere 256kbps (I think). The other is a 'whopping' 20Mbps.
The 20Mb connection is provided by XS4ALL, and the 256kbps is for free (if you have a phone subscription with Ziggo). The 256kbp is the minimum they provide to transport the phone calls, but if you're a masochist you can also browse the internet over that connection.

So, two ISP @ home. Combine that with a Juniper SRX firewall, and a dual ISP setup is born. The theory of that setup is that I connect both ISP's to the firewall, and use the 20Mb line as a default internet connection, but when that one dies, I automatically get switched to the backup line (256kbps).

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VMWare and Firewall / VPN Clients

Well, that was another morning well spent....

A couple off weeks ago I started experimenting with FreeRADIUS on Ubuntu server (v6.06.2 TLS). Mainly because I needed to test some things for work. So I used VMWare to experiment. The networking part was set-up as Bridged.

Today, I wanted to test with iperf (a tool for network performance testing). So I launched the virtual machine, but there was no network connectivity. ifconfig showed that eth1 didn't received an IP adres.
So I ran every possible test there was;

• restarted the interfaces (/etc/init.d/networking restart)

This resulted in the following;

Listening on LPF/eth1/00:0c:29:68:e3:eb
Sending on LPF/eth1/00:0c:29:68:e3:eb
Sending on Socket/fallback
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 8
DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 12

The "DHCPDISCOVER" messages continue about 4 times, then the message:

No DHCPOFFERS received.
No working leases in persistent database - sleeping.

• restarted the DHCP server
• rebooted the virtual machine
• changes the networking to NAT instead of Bridged (this way, connectivity was restored, but not the way I wanted. I needed Bridge-mode)
• Tried to run the virtual machine on OSX (VMWare Fusion), which worked surprisingly.

After this I ran Wireshark on my server to see if DHCP request were coming in.... And you might have guessed; No DHCP request were reaching the DHCP server. So the problem was work PC related.... As a matter of fact, I had the Cisco VPN client running..... Which didn't allow the DHCP request broadcast.

Shutting the VPN client down solved the DHCP problem. After the virtual machine worked I could reinitiate the VPN.

Mental note to myself: do NOT boot/restart the virtual machines when the VPN is up.