On Thu, 3 Mar 2005, Karalius, Joseph wrote: > Ken Herron wrote: > > It sounds like you might have another computer on your LAN using the > > same IP address. > > Ken wins! > The problem turned out to be someone else in IT was bringing a new printer > online with the same IP address. Doh!
... 20/20.... > I discovered this when I entered http://mmagdb/ for the 122nd time, and > instead of serving up the redirect from Apache, the Plone site, or nothing > at all, an HP printer status page from the offending piece of equipment came > up with confirmation of the duplicate IP. The printer was promptly brought > down and everything seems to be working as expected. Our WAN guy maintains > that he checked for duplicate IP addresses. He "checked"? Since the switch responds to whichever device sent a packet last, and the printer won't be emitting as many packets as an intranet server, the switch is likely to point to the server most of the time. > Why do the little things cause the biggest headaches? > > This is the second time I've run into duplicate IP address problems on this > network. The static IPs are mixed into the same host range with the DHCP > licensed IPs and IT's system for organizing them or notifying all personnel > of IP assignments has failed. It like they just hijack a number and don't > even ping for a response. I heard there's an Excel file somewhere that has > the reserved static IP addresses on it but changes to the file are not > propagated to everyone in the IT group. Huh? There's gotta be a better > way... Yes and no. If someone who thinks they know what is going on hijacks a number, you can't stop them. You have to have the cooperation of people using the network. > I spent the better part of the last 5 days fretting about this problem which > turned out to be because of lack of communication by IT. (Of course, if I > knew better, I should have explored that possibility further.) I plan to > address this with the parties involved, but instead of just ripping into > them I want to bring suggestions to the table. It's not my job to do either > of those but it's for their own good, since the next time they knock this > server out, the downtime will be far more expensive and they will get kicked > with a bigger boot from management. > > So, if I may redirect the discussion, I'd like to hear about how the network > admins on the list organize IP assignments. More specifically, is it wise > to put static IPs shuffled within the DHCP licensed host range and simply > blacklist the statics from the DHCP server? Unwise... and unusual. > Why not put the static IPs in a > different network, that way the address itself would tell you the address > type (static vs. dynamic) and if partitioned out even further, printers > could be in one host range on the network ,and servers could be in another. Not a different network, since that would imply different broadcast addresses... but you can use convention to subdivide the network. DHCP servers are specifically configurable to allow the administrator to set aside a range for allocating dynamic ip addresses. I setup a range for statics (usually near the bottom of the network address range), then a range for dynamic leases (near the top) and a third range for MAC-allocated DHCP addresses in the middle somewhere. > Is it common to just ping addresses to find an unused one and then grab it? Common? depends which idiot is handing out the advice. > Or is this a non-issue and only newbies and hacks are affected by it? It is always an issue as an organization grows larger. I don't manage a large network so I don't speak from experience, but I would advocate a visible, public (within the organization) document like a web page for making the policy clear and providing instructions for who to talk to about adding equipment that doesn't use DHCP. I think it is important to enlist people's cooperation, because failing to do so leads to these problems. --------------------------------------------------------------------------- Jeff Newmiller The ..... ..... Go Live... DCN:<[EMAIL PROTECTED]> Basics: ##.#. ##.#. Live Go... Live: OO#.. Dead: OO#.. Playing Research Engineer (Solar/Batteries O.O#. #.O#. with /Software/Embedded Controllers) .OO#. .OO#. rocks...1k --------------------------------------------------------------------------- _______________________________________________ vox-tech mailing list [email protected] http://lists.lugod.org/mailman/listinfo/vox-tech
