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brugernavn 0 Newbie Poster

Hello =)

I have a lilte problem with my dhcp server..

when i try to start isc up.. i got this message "failed to start"

syslog:

Jul 1 15:31:11 nectioon-home-server dhcpd: Internet Systems Consortium DHCP Server 4.1-ESV-R4
Jul 1 15:31:11 nectioon-home-server dhcpd: Copyright 2004-2011 Internet Systems Consortium.
Jul 1 15:31:11 nectioon-home-server dhcpd: All rights reserved.
Jul 1 15:31:11 nectioon-home-server dhcpd: For info, please visit https://www.isc.org/software/dhcp/
Jul 1 15:31:12 nectioon-home-server kernel: [ 1511.299010] dhcpd[2023]: segfault at 7f74434ff000 ip 00007f7443dd14aa sp 00007fffe8f86158 error 7 in libc-2.15.so[7f7443d3b000+1b3000]
Jul 1 15:31:12 nectioon-home-server kernel: [ 1511.333109] init: isc-dhcp-server pre-start process (2021) terminated with status 139

my dhcpd.conf:

    option domain-name "domain.eu";
    option domain-name-servers 8.8.8.8, 8.8.4.4;

    default-lease-time 9999;
    max-lease-time 9999;

    option subnet-mask 255.0.0.0;
    option broadcast-address 91.100.21.62;
    option routers 91.100.21.28;

    subnet 10.0.0.0 netmask 255.0.0.0 {
    range 10.0.0.1 10.254.254.254;


    host server1 {
    hardware ethernet 08:00:27:14:17:0a;
    fixed-address 10.162.162.5;
    }
    }

everything is runnng with no problem, if i use a "Class C" ip-range.. i only got the problems when i use a "Class A" ip-range..

So, what is wrong here?

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Dani AI

Generated

— the kernel message and “terminated with status 139” mean the dhcpd process is crashing with a segmentation fault (SIGSEGV). Treat this as a daemon crash triggered by something in the runtime environment (usually the config, leases file, or a known bug in that dhcpd build), not a simple service start failure. (wiki.ubuntu.com)

Quick, safe diagnostics to run on the server (don’t restart the system service while testing):

  • Syntax- and leases-check first:
    sudo dhcpd -t -cf /etc/dhcp/dhcpd.conf -lf /var/lib/dhcp/dhcpd.leases
  • Run dhcpd in the foreground with debug logging so it prints where it dies:
    sudo dhcpd -4 -f -d -cf /etc/dhcp/dhcpd.conf

    The dhcpd manpage documents these options and the -T/-lf checks for leases. (docs.oracle.com)

Common configuration causes and quick fixes to try next: ISC’s knowledge base and past bug reports show segfaults from circular/recursive option expressions, evaluated regular expressions, and even malformed/huge configs or large blocks of whitespace. Reduce the file to a minimal working subnet block and reintroduce lines until it breaks. Also check for mismatched/global options — e.g., router/broadcast addresses set for a different network than the subnet you declared; move network-specific options inside the correct subnet. Inspect and, if necessary, restore the leases file from its backup rather than creating a new one. (kb.isc.org)

If the crash persists, capture a core/backtrace: set ulimit -c unlimited, reproduce the crash, then use gdb on the core to get a backtrace (or run the foreground command under gdb). That backtrace is the key data to decide if this is a config problem you can fix or a package bug that needs upgrading or reporting. Instructions and wrapper examples for capturing backtraces are here. (serverfault.com)

Checklist summary: 1) dhcpd -t and check leases; 2) run dhcpd -f -d to see the crash; 3) simplify config (split /8 into smaller test ranges); 4) capture core + gdb backtrace; 5) if it’s a reproducible crash in 4.1, test a newer isc-dhcp build or report with logs+backtrace.

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