Question:

I need to take my laptop to a customer site and connect to their network. They say I need to use DHCP. I use static routing on my SOHO network. I know I can use MPTS to reconfigure, but there must be an easier way. What does Mr. KIA have to say about this?

Answer:

IBM's TCP/IP stack is pretty flexible. Most of the TCP/IP settings can be changed dynamically. The means you can do the switching from the command line.

Let's say your setup.cmd for your static routing setup looks like:

 route -fh
 ifconfig lo 127.0.0.1
 ifconfig lan0 192.168.0.2 netmask 255.255.255.0
 ifconfig lan0 mtu 1492
 route add default 192.168.0.1 -hopcount 1 
 ipgate off

  route -fh
  ifconfig lan0 down
  start dhcpmon
  dhcpstrt -i lan0

Mr. KIA has been told that some TCP/IP stacks kill the loopback interface when DHCP is enabled. If this occurs, use:

  ifconfig lo 127.0.0.1

If you have problems, check \mptn\etc\dhcpcd.cfg. The following set of option requests is usually sufficient.

 option 1                                 # Subnet Mask
 option 3                                 # Router
 option 6                                 # Domain Name Server
 option 15                                # Domain Name
 option 28                                # Broadcast Address
 option 33                                # Static Routes
 option 60 "IBMWARP_V3.1"                 # Vendor Class
 option 77 "IBMWARP_V3.1"                 # User Class

Most sites will not allow direct browser access from their intranet to the internet. Typically, there will be a proxy server. If so, ask your customer for the proxy server URL or IP address and configure the browser to use these values. For Mozilla, the settings are at Edit -> Preferences -> Advanced -> Proxies.

When you are done, you'll want to shut down the DHCP setup and return to your normal setup.

To shut down the DHCP setup, use the DHCP Monitor to release the lease. After releasing the lease, shut down the DHCP Monitor. Then issue the following commands:

  route -fh
  dhcpmon -t
  setup

Check that RESOLV or RESOLV2 have returned to their original values. If not, restore the copies you saved.

If you configured the browser for a proxy, restore the original settings so that the browser will work when you get back to the office.

That's all there is to it.

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