Network Address getting assigned to client and ping not working (ver 4.2.2)

Lyle Giese lyle at lcrcomputer.net
Tue Apr 24 13:50:03 UTC 2012


On 04/24/12 08:30, Mukund Deshpande wrote:
> Hi All,
>
> I am facing two issues when using ISC DHCP (Using version 4.2.2).
>
> When I keep a network address like 7.7.7.0 in range it gets assigned 
> on client.
> Is this correct behavior?
>
> Also when i try to ping on the address assigned by dhclient on an 
> interface i get error "connect: Invalid Argument" , even when i have 
> host addresses in range.
> Can any body please provide me with pointers as to why ping doesn't work?
>
>
> #
> # /etc/dhcpd.conf - DHCP Server Setup File.
> #
>
> # DHCP Pool sms
> subnet 7.7.7.0 netmask 255.255.255.0 {
>  option subnet-mask 255.255.255.0;
>  range 7.7.7.0;
>  default-lease-time 86400;
>  max-lease-time 86400;
> }
> ddns-update-style none;
>
>
> Running dhclient as
>
>  [root at Marvell1 ~]#/usr/sbin/dhclient -4 -cf /etc/dhclient-eth1.conf 
> -lf /etc/dhclient-eth1.leases -pf /var/run/dhclient-eth1.pid eth1
>
> Captured on Client
> --------------------------------
>
> [root at Marvell1 ~]# tethereal -i eth1
> Running as user "root" and group "root". This could be dangerous.
> Capturing on eth1
>   0.000000      0.0.0.0 -> 255.255.255.255 DHCP DHCP Discover - 
> Transaction ID 0xf7d8ad21
>   1.016566      7.7.7.1 -> 7.7.7.0      DHCP DHCP Offer    - 
> Transaction ID 0xf7d8ad21
>   1.016965      0.0.0.0 -> 255.255.255.255 DHCP DHCP Request  - 
> Transaction ID 0xf7d8ad21
> *  1.037018      7.7.7.1 -> 7.7.7.0      DHCP DHCP ACK      - 
> Transaction ID 0xf7d8ad21 * <<<<<<<<<<<<< Assigning Network Address
> ^C4 packets captured
> [root at Marvell1 ~]# ifconfig eth1
> eth1      Link encap:Ethernet  HWaddr 00:1B:21:52:AD:69
>           inet addr:7.7.7.0  Bcast:7.7.7.255  Mask:255.255.255.0
>           inet6 addr: fe80::21b:21ff:fe52:ad69/64 Scope:Link
>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>           RX packets:19583 errors:2 dropped:0 overruns:0 frame:2
>           TX packets:66453 errors:11 dropped:0 overruns:0 carrier:11
>           collisions:0 txqueuelen:1000
>           RX bytes:1854865 (1.7 MiB)  TX bytes:5472310 (5.2 MiB)
>
> *[root at Marvell1 ~]# ping 7.7.7.0 <<< This happens whenever dhclient is 
> running...*
> *connect: Invalid argument*
>
>
> Lease File
> -------------------
>
> [root at Marvell1 etc]# cat dhclient-eth1.leases
> lease {
>   interface "eth1";
>   fixed-address 7.7.7.0;
>   option subnet-mask 255.255.255.0;
>   option dhcp-lease-time 86400;
>   option dhcp-message-type 5;
>   option dhcp-server-identifier 7.7.7.1;
>   renew 4 2012/04/26 21:10:20;
>   rebind 5 2012/04/27 08:32:20;
>   expire 5 2012/04/27 11:32:20;
> }
>
>
> Captured on Server
> --------------------------------
> /mukund/home/zebos # /tcpdump -i ge1
> device ge1 entered promiscuous mode
> tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
> listening on ge1, link-type EN10MB (Ethernet), capture size 65535 bytes
> 16:57:39.482239 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, 
> Request from 000
> 16:57:40.498253 IP 7.7.7.1.67 > 7.7.7.0.68: BOOTP/DHCP, Reply, length 300
> 16:57:40.499162 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, 
> Request from 000
> 16:57:40.518704 IP 7.7.7.1.67 > 7.7.7.0.68: BOOTP/DHCP, Reply, length 300
> -- 
> Regards,
> Mukund
>
>
>
> _______________________________________________
> dhcp-users mailing list
> dhcp-users at lists.isc.org
> https://lists.isc.org/mailman/listinfo/dhcp-users
1) Range = Subnet in your config.  Results will be indeterminate because 
of that.  It has also been suggested that using .0 or .255 in the last 
octet of an IPv4 address can be problematic because of assumptions/bugs 
in IPv4 implementations in various OS/devices.

2) Newer windows OS's block icmp packets by default.  Make sure the 
target OS is not firewalling ping packets.

Lyle Giese
LCR Computer Services, Inc.

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