[Info-vax] SOLVED: Re: tcpip gateway question

[Richard B. Gilbert]

urbancamo wrote:
> Wow, I'm glad I decided to check comp.os.vms as I have the same
> problem, but a much simpler context. A hobbyiest network, one subnet,
> several machines served their ethernet addresses via dhcp running
> under NetBSD. Everything was fine until I installed decnet on the
> ZX6000. What's intriging about reading through the previous posts is
> the conversation about when the MAC address is changed.
> 
> On the ZX6000 I have:
> 
> $ tcpip show interface we0/full
>  Interface: WE0
>    IP_Addr: 192.168.1.57      NETWRK: 255.255.255.0     BRDCST:
> 192.168.1.255
>                        Ethernet_Addr: AA-00-04-00-FB-04    MTU:  1500
>      Flags: UP BRDCST NOTRL RUN MCAST SMPX
>                                   RECEIVE        SEND
> 
> However, if I monitor the DHCP log I get the following as the TCP/IP
> stack starts up on OpenVMS:
> 
> Oct  2 22:13:16 dell7500 dhcpd: DHCPREQUEST for 192.168.1.230 from
> 00:30:6e:f3:2c:a5 via ex0: unknown lease 192.168.1.230.
> 
> The request fails because I've configured the DHCP server with the MAC
> address reported by OpenVMS.
> 
> So what's going on here? If I configure DHCP to serve on the hardware
> MAC address I get the symptoms where I can telnet/ping any box on the
> subnet but *not* the gateway.
> 
> Regards, Mark.
> 

I'm not certain but I suspect that your problem is due to the fact that 
DECnet sets the Ethernet address to AA-00-04-00-FB-04.  If you start 
TCP/IP first, it will get the original hardware address for the 
interface.  When DECnet starts it will set the address to the DECnet 
node address and leave TCP/IP swinging in the breeze!

So start DECnet first and then TCP/IP.  Alternatively, you can decide 
not to start DECnet at all.  Don't change your mind in mid stream!  If 
you start TCP/IP and then DECnet, DECnet will change the Ethernet 
address and screw up TCP/IP!!