Stoppt die Vorratsdatenspeicherung! Jetzt klicken &handeln! Willst du auch an der Aktion teilnehmen? Hier findest du alle relevanten Infos und Materialien:
Jump to menu and information about this site.

Friday·07·January·2011

“peer holds all free leases” on both DHCP servers //at 15:54 //by abe

from the not-so-helpful-error-messages dept.

At work we run a pair of ISC DHCP servers running Debian Lenny in a classical ISC DHCP failover setup which provide DHCP service to several subnets, some only with static IPs (e.g. for printers) and some with half static and half dynamic IPs.

Today I got a call from a user that her laptop doesn’t get an IP despite it’s correctly registered in our MAC address database from which we generate the “group { }” sections of the dhcpd.conf.

Everything looked fine, but every DHCPDISCOVER package got logged in the syslog on both servers like this:

Jan  7 14:34:39 dhcp1 dhcpd: DHCPDISCOVER from 01:23:45:67:89:ab via eth2: peer holds all free leases
Jan  7 14:34:39 dhcp2 dhcpd: DHCPDISCOVER from 01:23:45:67:89:ab via eth2: peer holds all free leases

Searching the web for this error message mostly results in mails which say “If have this on one server but not the other, you soon run out of IP addresses”, but none which mentions what happens if you got them on both sides. Following a coworker’s idea of adding “both servers” to the search term, I found Debian bug #563449 (dhcp3-server: Incorrect “peer holds all free leases” log entries) which turned out as configuration error or at least unexpected configuration (machine was blocked from getting an IP on purpose) and misleading error messages.

So I checked under which circumstances this computer would not get an IP despite it had a static IP configured:

  host somehost {
    hardware ethernet 01:23:45:67:89:ab;
    fixed-address 192.0.2.123;
  }

That computer would not get an IP address in any subnet which has different IP range and no dynamic IP addresses. And even if I comment out the “fixed-address” setting, it wouldn’t get an IP in any static-IPs-only subnet either.

And *bingo*, that computer was plugged into the printer subnet which has only static IPs, e.g. in the 198.51.100.x range.

So if you get the “peer holds all free leases” error message from both your DHCP servers, chances are very high that the mentioned MAC address should really not get an IP address on this network (as it does :-). The error messages are just somewhat misleading.

Hope, this saves someone some time. :-)

Tag Cloud

2CV, aha, Apache, APT, aptitude, ASUS, Automobiles, autossh, Berlin, bijou, Blogging, Blosxom, Blosxom Plugin, Browser, BSD, CDU, Chemnitz, Citroën, CLI, CLT, Conkeror, CX, deb, Debian, Doofe Parteien, E-Mail, eBay, EeePC, Emacs, Epiphany, Etch, ETH Zürich, Events, Experimental, Firefox, Fläsch, FreeBSD, FVWM, Galeon, Gecko, git, GitHub, GNOME, GNU, GNU Coreutils, GNU Screen, Google, GPL, grep, grml, gzip, Hackerfunk, Hacks, Hardware, Heise, HTML, identi.ca, IRC, irssi, Jabber, JavaShit, Kazehakase, Lenny, Liferea, Linux, LinuxTag, LUGS, Lynx, maol, Meme, Microsoft, Mozilla, Music, mutt, Myon, München, nemo, Nokia, nuggets, Open Source, Opera, packaging, Pentium I, Perl, Planet Debian, Planet Symlink, Quiz, Rant, ratpoison, Religion, RIP, Sarcasm, Sarge, Schweiz, screen, Shell, Sid, Spam, Squeeze, SSH, Stöckchen, SuSE, Symlink, Symlink-Artikel, Tagging, Talk, taz, Text Mode, ThinkPad, Ubuntu, USA, USB, UUUCO, UUUT, VCFe, Ventilator, Vintage, Wahlen, Wheezy, Wikipedia, Windows, WML, Woody, WTF, X, Xen, zsh, Zürich, ÖPNV

Calendar

 2011 
Months
Jan
 January 
Mo Tu We Th Fr Sa Su
         
7
           

Tattletale Statistics

Blog postings by posting time
Blog posting times this month



Search


Advanced Search


Categories


Recent Postings

0 most recent of 0 postings total shown.


Recent Comments

Hackergotchi of Axel Beckert

About...

This is the blog or weblog of Axel Stefan Beckert (aka abe or XTaran) who thought, he would never start blogging... (He also once thought, that there is no reason to switch to this new ugly Netscape thing because Mosaïc works fine. That was about 1996.) Well, times change...

He was born 1975 at Villingen-Schwenningen, made his Abitur at Schwäbisch Hall, studied Computer Science with minor Biology at University of Saarland at Saarbrücken (Germany) and now lives in Zürich (Switzerland), working at the IT Support Group (ISG) of the Departement of Physics at ETH Zurich.

Links to internal pages are orange, links to related pages are blue, links to external resources are green and links to Wikipedia articles, Internet Movie Database (IMDb) entries or similar resources are bordeaux. Times are CET respective CEST (which means GMT +0100 respective +0200).


RSS Feeds


Identity Archipelago


Picture Gallery


Button Futility

Valid XHTML Valid CSS
Valid RSS Any Browser
GeoURL
This content is licensed under a Creative Commons License (SA 3.0 DE). Some rights reserved. Hacker Emblem
Get Mozilla Firefox! Powered by Linux!
Typed with GNU Emacs Listed at Tux Mobil
XFN Friendly Button Maker

Blogroll

Blog or not?


People I know personally


Other blogs I like or read


Independent News


Interesting Planets


Web comics I like and read

Stalled Web comics I liked


Blogging Software

Blosxom Plugins I use

Bedside Reading

Just read

  • Bastian Sick: Der Dativ ist dem Genitiv sein Tod (Teile 1-3)
  • Neil Gaiman and Terry Pratchett: Good Omens (borrowed from Ermel)

Currently Reading

  • Douglas R. Hofstadter: Gödel, Escher, Bach
  • Neil Gaiman: Keine Panik (borrowed from Ermel)

Yet to read

  • Neil Stephenson: Cryptonomicon (borrowed from Ermel)

Always a good snack

  • Wolfgang Stoffels: Lokomotivbau und Dampftechnik (borrowed from Ermel)
  • Beverly Cole: Trains — The Early Years (getty images)

Postponed