Newsgroups: comp.dcom.sys.cisco
Path: utzoo!utgpu!cunews!bnrgate!bwdls61!bwdls49!tonyf
From: tonyf@bwdls49.bnr.ca (Tony Farrow)
Subject: Re: all of the ethernets interfaces with the same address!?
Message-ID: <1991Apr3.203326.388@bwdls61.bnr.ca>
Keywords: CISCO Sun
Sender: usenet@bwdls61.bnr.ca (Use Net)
Reply-To: tonyf@bwdls49.bnr.ca (Tony Farrow)
Organization: bnr
References: <33874@boulder.Colorado.EDU> <1991Apr3.155233.17045@wdl1.wdl.loral.com>
Date: Wed, 3 Apr 1991 20:33:26 GMT

In article <1991Apr3.155233.17045@wdl1.wdl.loral.com>, wrl@wdl1.wdl.loral.com (Bill Lewandowski) writes:
|> In article <33874@boulder.Colorado.EDU> BILLW@mathom.cisco.com (WilliamChops Westfield) writes:
|> >
|> >    In all TCP/IP implementations I know of, all ports on the
|> >    same machine use the same ethernet (hardware) address.  On
|> >    initialization, it reads the ROM on the first port it finds,
|> >    and stores this in all the ports.  
|> >
|> Bill, sorry to say but suns have done this to us. Last year we were changing
|> from network 128.5.0.0 to 137.249.0.0. We wanted to have a machine with
|> two ethernet interfaces on the same ethernet cable segment so we could have
|> continous Name Server service (one on each subnet) when the NIC flipped us
|> and until all the hosts.txt got caught up.
|> 
|> We had problems because the sun on bootup made both ethernet cards the same hardware
|> address. We had to put a separate hardware address in the "ifconfig" statement for
|> the second ethernet card in order for us not to get duplicate packets.
|> (I got a lot of help on this from the "sun-nets" list)
|> 

    We had the same problem here with our multi-homed Sun File Servers.
    We got around the problem by using unique ethernet
    addresses given to us by Sun for our dual interface servers via ifconfig
    options. Our problem did not cause us much grief as our unique ethernet 
    addresses were only needed per IP subnet and each of the interfaces 
    were on different IP subnets.

regards,
tony
    

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