dhcpd handing out wrong gateway

[Simon Hobson]

Fredrik Björk wrote:

>I'm not actually asking for help to debug config files

Actually, yes you are, but you just don't realise it !

The DHCP server is normally quite reliable and 
handing out the wrong options isn't something it 
normally does - unless wrongly configured. And 
now I see your config, I spot immediately that my 
hunch was correct.

You have declared some host configs inside a 
shared-subnet declaration. Except under very 
limited circumstances which require you to 
**really really** know what you're doing, never 
ever do this. Host declarations are global in 
scope, so options defined there will override 
options inherited from a subnet.

So, say host "special" gets connected to a 
different network. It will be given an IP address 
from that new network but it will also inherit 
the options declared in it's host declaration. 
Bingo - you've now got a host with an IP address 
correct for it's network, but the wrong gateway 
address.

>shared-network BSR3CPE {
>         subnet 123.123.230.0 netmask 255.255.255.0 {
>                 option routers 123.123.230.1;
>                 pool {
>                         range 123.123.230.40 123.123.230.254;
>                         deny members of "16-6M-DHCP";
>                         deny members of "Static00223a4e8017";
>                 }
>                 pool {
>                         range 123.123.230.2 123.123.230.39;
>                         allow members of "16-6M-DHCP";
>                 }
>         }
>         subnet 123.123.233.0 netmask 255.255.255.0 {
>                 option routers 123.123.233.1;
>                 max-lease-time 600;
>                 default-lease-time 600;
>                 pool {
>                         range 123.123.233.65 123.123.233.254;
>                 }
># The below "SpecialX" were handed out to people 
>who experienced the "gateway problem". Separate 
>host declarations solved their problems!
>host special {
>hardware ethernet 00:19:99:a0:51:13;
>option routers 123.123.233.1;
>fixed-address 123.123.233.33;
>}
>host special2 {
>hardware ethernet 00:21:91:ed:b3:bb;
>option routers 123.123.233.1;
>fixed-address 123.123.233.34;
>}
>host special3 {
>hardware ethernet 00:25:9c:34:fc:55;
>option routers 123.123.233.1;
>fixed-address 123.123.233.35;
>}
>host special4 {
>hardware ethernet 00:11:22:33:ef:ef:ef;  # Dummy. For future use...
>option routers 123.123.233.1;
>fixed-address 123.123.233.36;
>}
>         }
>         subnet 123.123.231.0 netmask 255.255.255.0 {
>                 option routers 123.123.231.1;
>                 pool {
>                         deny members of "Static001e6bec1635";
>                         deny members of "Static00223a4e8017";
>                         range 123.123.231.13 123.123.231.254;
>                 }
>                 pool { allow members of 
>"Static001e6bec1635"; range 123.123.231.8 
>123.123.231.8; }
>                 pool { allow members of 
>"Static00223a4e8017"; range 123.123.231.9 
>123.123.231.9; }
>                 pool {
>                         allow members of "Static0018c022a3be";
>                         range 123.123.231.10 123.123.231.10;
>                 }
>         }
>}
>
>
>shared-network CASACPE {
>         subnet 123.123.235.0 netmask 255.255.255.0 {
>                 option routers 123.123.235.1;
>                 include "/etc/dhcpd.static235";
>                 pool {
>                         max-lease-time 600;
>                         default-lease-time 600;
>                         allow members of "MTA";
>                         range 123.123.235.250 123.123.235.254;
>                 }
>                 pool {
>                         max-lease-time 600;
>                         default-lease-time 600;
>                         allow unknown clients;
>                         range 123.123.235.240 123.123.235.249;
>                 }
>         }
>         subnet 123.123.237.0 netmask 255.255.255.0 {
>                 option routers 123.123.237.1;
>                 pool {
>                         max-lease-time 1200;
>                         default-lease-time 1200;
>                         deny members of "MTA";
>                         deny unknown-clients;
>                         range 123.123.237.2 123.123.237.254;
>                 }
>         }
>         subnet 123.123.238.0 netmask 255.255.255.0 {
>                 option routers 123.123.238.1;
>                 pool {
>                         max-lease-time 1200;
>                         default-lease-time 1200;
>                         allow members of "MTA";
>                         range 123.123.238.2 123.123.238.254;
>                 }
>         }
>}
>
>


-- 
Simon Hobson

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