[CLUE-Tech] Forcing TCP/IP Address - RedHat 7.3

[Frank Whiteley]

In the routers I've worked with that have DHCP server, you can define/limit
your DHCP range say to 10.0.0.4-10.0.0.20, then assign static IPs on the
same subnet to permanent setups.  So, if your router gateway is 10.0.0.1,
you can use 10.0.0.2, 10.0.0.3, or >10.0.0.20 for your statics.  Then when
you add/delete a PC/laptop, it'll grab from the DHCP range and be able to
talk to the rest of your network.  I'm assuming that's your reason for using
DHCP.

That being said, I normally recommend staying away from 10.0.0.X subnets,
since these get overused and inadvertantly broadcast and cause router
flapping.  See http://www.cis.ohio-state.edu/cgi-bin/rfc/rfc1918.html for
acceptible ranges.  I know we had a school district set up an internal DNS
server for their domain and hooked it somehow into their DNS records at
cw.net.  This caused e-mail to not get through because it created a router
flap with a local ISP that was using the same subnet for their LAN.

Frank Whiteley

----- Original Message -----
From: "Mike Benavides" <tipsrules99 at attbi.com>
To: <clue-tech at clue.denver.co.us>
Sent: Sunday, July 28, 2002 11:42 AM
Subject: Re: [CLUE-Tech] Forcing TCP/IP Address - RedHat 7.3


>
> > Two things...  dhcpd can be set up to assign IP X to MAC address Y...
(or at
> > least the linux version of dhcpd can.. don't know about your router.
Also,
> > most DHCP clients will ask the server for the IP that they had last
time,
> > and it will tell them if they can have it or not.  I know in Windows
this is
> > the default..  If linux isn't doing it, try checking the docs for dhcpcd
or
> > pump to see if they can do it.
> >
> > Jeremy
> > ----- Original Message -----
> > From: "Gary Threlkeld" <gthrelk at attbi.com>
> > To: "CLUE-Tech" <clue-tech at clue.denver.co.us>
> > Sent: Saturday, July 27, 2002 7:40 PM
> > Subject: [CLUE-Tech] Forcing TCP/IP Address - RedHat 7.3
> >
> >
> > > Hello Network Gru's -
> > >
> > > I'm trying to CONSISTANTLY get two machines to talk to one another.
> > > My problem currently is that I have a router that has DHCP turned.  It
> > > assigns machines IP addresses in the order in which machines log onto
> > > the network such as:
> > >
> > > Router:     192.168.2.1
> > > Tom:        192.168.2.100
> > > Dick:        192.168.2.101
> > >
> > > If I set the /etc/host file to reflect these IP addresses and the
> > > machines are logged onto the network in the order of Tom first and
> > > Dick second, the machines can find each other by their names OK -
> > > (such as ping Tom or ping Dick).  But if the machines are logged onto
> > > the network in a different order, their assigned IP addresses are
> > > swapped - and they can't find each other.
> > >
> > > I can turn off DHCP but my question is how do I force setting of each
> > > machine's TCP/IP address so that it is consistantly assigned the same
> > > IP address on the network?
> > >
> > > Thanks,
> > >
> > > Gary Threlkeld
> > > Email:      gthrelk at attbi.com
> > >
> > >
> > >
> Gary et al;
> If you want to use static IPs you must turn off DHCP of the router. Set
> up the router with the static IP that you are using in you're /etc/hosts
> file. This has worked for me of my Linksys router in the past. also
> check your routing routing tables.
>
> Mike Benavides
>
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