[afnog] Problem with DHCP Relay on Cisco 3725 Router

[Jaco Engelbrecht]

Hi,

Hosea Phiri wrote:
> Is there anything you are suspecting? Let me know if my detail is insufficient.

Your DHCP helper configuration is correct.

Here's a few things to check:

- I assume that you can ping 192.168.3.20 from your router?

- Have you tried running tcpdump (tcpdump -lenX -s 1500 port bootps or
port bootpc) on your DHCP server, to see if you're receiving any DHCP
requests from your router?

- Is there a possible iptables/ipfw rule blocking DHCP requests to your
DHCP server?

- It might be handy to run dhcpd with the "-d" option.

- Are you using the shared-network declaration option in your dhcpd.conf
for your 192.168.30.0 network?

- If you're not seeing anything on your DHCP server, try "debug ip udp"
on your router - but see
http://www.cisco.com/en/US/docs/ios/12_2/debug/command/reference/dbfippim.html#wp1037927
first!

This is my DHCP configuration that I use for kickstarting FreeBSD and
Ubuntu servers:

--
#
# Options
authoritative;
ddns-update-style none;
default-lease-time 600;
max-lease-time 7200;

#
# Logging
log-facility local7;

#
# Kickstart shared network
shared-network kickstart {

  ## Mail subnet
  subnet 172.20.80.0 netmask 255.255.255.0 {

        option subnet-mask 255.255.255.0;
        option routers 172.20.80.2;
        option domain-name-servers 172.20.69.7, 172.50.16.72;
        option domain-name "serendipity.org.za";
        deny unknown-clients;

        host slowrelay {
                hardware ethernet 00:0E:7F:27:23:B8;
                fixed-address 172.20.80.40;
                filename "freebsd/6.2/pxeboot";
                option root-path "172.20.80.10:/export/tftpboot/6.2";
        }
  }

  ## Sysarch subnet
  subnet 192.168.83.0 netmask 255.255.255.128 {
       option subnet-mask 255.255.255.128;
       option routers 192.168.83.1;
       option domain-name-servers 172.20.69.7, 172.50.16.72;
       option domain-name "sysarch.serendipity.org.za";
       deny unknown-clients;

       host xen01 {
               hardware ethernet 00:1c:c4:3a:f2:7c;
               fixed-address 195.8.83.10;
               filename "ubuntu/feisty/ubuntu-installer/amd64/pxelinux.0";
       }

  }

}

--

Hope that helps.

Jaco

-- 
bje at serendipity.org.za
the faculty of making fortunate discoveries