Hardware-address with IP-address

[Kirsten Knüttel]

Hi,

I'm using TCPIP V. 5.3 Eco2 and have a question. For a program I need the following thing. I have the IP-address of a client and I'm now searching for the hardware / mac-address. Normally we use TCPIP show arp but at the moment (the collegues are installing a new network) I don't receive the hardware address.
Under windows I can use for this
nbtstat -A ip-address
Does I have something like this under VMS, too or does somebody know another way to find the hardware address when I only have the IP-address?

Regards,

Kirsten

[Karl Rohwedder]

I assume that in that case a

$ TCPIP netstat "-H"

doesn't work either (don't know for sure if it is supported under V5.3)?

regards Kalle

[Volker Halle]

Kirsten,

I don't think there is any way to obtain the remote node's hardware address, if that node is not currently connected to the network and it's entries in the ARP cache have timed out.

Volker.

[Kirsten Knüttel]

Hi Volker,

the problem is, that the client is connected to the network, I can ping the client, no problem. Under windows with nbtstat I receive the hardware address. But I don't know a way under VMS.

Regards,

Kirsten

[Volker Halle · Accepted solution]

Kirsten,

then the client is most probably on another LAN and you are communicating to the client via a router. ARP only works on the local LAN. You would have to ask the router about the client's hardware address.

nbtstat may only show you the client's hardware address, IF any NetBIOS over TCP/IP connection is currently active.

Volker.

[Willem Grooters]

A wild shot or hint: could SNMP deliver the requested information (it must then be enabled, I know)

[Uwe Zessin]

Another reason why you might not be able to find it out from a remote system is if there is a router between both nodes.

[Joseph Huber_1]

TCPIP netstat "-H" (or "netstat -H" after executing TCPIP$DEFINE_COMMANDS.COM) does work under TCPIP 5.3 as well.

But as said, it needs the address in the ARP tables.

Maybe a difference to Windoze is: the TCPIP services ARP cache interval seems to be shorter.