dhcp ip

[shaikhaltamash291]

Dear sir,

I have a cicso 1905 router in my office 

i have configured the dhcp as 

ip dhcp excluded-address 10.10.13.1 10.10.13.50
!
ip dhcp pool LAN_POOL
network 10.10.13.0 255.255.255.0
default-router 10.10.13.1

the dhcp clients not getting ip range in sequences below mentioned 

getting alternate ips and due to which pool is full please suggest any renew or release command

to work it out 

		Internet  10.10.13.124            1   2c41.389a.7724  ARPA   GigabitEthernet0/1
		Internet  10.10.13.125            0   4061.86e4.e2f7  ARPA   GigabitEthernet0/1
		Internet  10.10.13.131            0   8cdc.d43b.1fe7  ARPA   GigabitEthernet0/1
		Internet  10.10.13.132            0   Incomplete      ARPA
		Internet  10.10.13.138            0   8cdc.d43a.64f2  ARPA   GigabitEthernet0/1
		Internet  10.10.13.142            0   8cdc.d43a.6533  ARPA   GigabitEthernet0/1
		Internet  10.10.13.144            1   2c41.389a.766f  ARPA   GigabitEthernet0/1
		Internet  10.10.13.145            0   8cdc.d43b.1fbd  ARPA   GigabitEthernet0/1
		Internet  10.10.13.146            0   8cdc.d43b.1f86  ARPA   GigabitEthernet0/1
		Internet  10.10.13.150            1   2c41.389a.746d  ARPA   GigabitEthernet0/1
		Internet  10.10.13.151            5   000f.e032.cb60  ARPA   GigabitEthernet0/1
		Internet  10.10.13.157            0   4061.8634.b45e  ARPA   GigabitEthernet0/1
		Internet  10.10.13.158            0   2c41.389a.73c1  ARPA   GigabitEthernet0/1
		Internet  10.10.13.166            5   0010.c6a8.6a59  ARPA   GigabitEthernet0/1
		Internet  10.10.13.167            0   8cdc.d439.f94d  ARPA   GigabitEthernet0/1
		Internet  10.10.13.170            0   8cdc.d43b.38ec  ARPA   GigabitEthernet0/1
		Internet  10.10.13.173            0   2c41.389a.6272  ARPA   GigabitEthernet0/1
		Internet  10.10.13.176            2   0023.ae9f.72ba  ARPA   GigabitEthernet0/1
		Internet  10.10.13.186            3   0010.c6a8.78fa  ARPA   GigabitEthernet0/1
		Internet  10.10.13.193            0   4061.86e4.ea45  ARPA   GigabitEthernet0/1
		Internet  10.10.13.197            0   8cdc.d43a.6532  ARPA   GigabitEthernet0/1
		Internet  10.10.13.200            1   2c41.389a.74e7  ARPA   GigabitEthernet0/1
		Internet  10.10.13.210            0   0021.9b3e.b2b8  ARPA   GigabitEthernet0/1
		Internet  10.10.13.226            4   000f.e032.ca42  ARPA   GigabitEthernet0/1
		Internet  10.10.13.228            0   4061.8634.b407  ARPA   GigabitEthernet0/1
		Internet  10.10.13.230            1   4061.8634.b053  ARPA   GigabitEthernet0/1
		Internet  10.10.13.239            0   8cdc.d43b.191f  ARPA   GigabitEthernet0/1
		Internet  10.10.13.246            2   2c41.389a.7300  ARPA   GigabitEthernet0/1
		Internet  10.10.13.248            2   4061.86e4.ea2a  ARPA   GigabitEthernet0/1

[Tagir Temirgaliyev]

sh ip dhcp bin

sh ip dhcp conf

[Giuseppe Larosa]

Hello Shaikhaltamash291,

the configuration should allow the DHCP server to server IP addresses from 10.10.13.51 to 10.10.13.254 to requesting clients.

see

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_dhcp/configuration/15-mt/dhcp-15-mt-book/config-dhcp-server.html

As already mentioned you can use the

show ip dhcp binding

to see the current use of the DHCP pool, there is no way to force the router to assign consecutive IP addresses, however it should be able to assign IP addresses until the pool is not really full.

Have you checked with debug commands that the DHCP server is unable to assign IP addresses even there are many free in the pool?.

There are some debug commands related to DHCP server activity:

00100SW1B#debug ip dhcp server ?
binding-store Binding data store
class Class-based address allocation
events Report address assignments, lease expirations, etc.
linkage Show database linkage
packet Decode message receptions and transmissions
redundancy DHCP server redundancy events
snmp DHCP server snmp events

I suggest using debug ip dhcp server events

you need terminal monitor to see debug output on your telnet/SSH session.

Only after a deep analysis with debug commands and comparing messages with the contents of show ip dhcp binding you can come to the conclusion that the router is misbehaving.

If this is the case, I have seen some cases in the past, you may want to consider an IOS upgrade, if you have a valid contract you can download a newer IOS image for your device and hopefully the DHCP issue will be solved.

Hope to help

Giuseppe

[shaikhaltamash291]

Thank you sir   

[shaikhaltamash291]

Dear Sir

i have cisco 1900 router in my office i have configured dns and dhcp as

mention below .my dhcp client is getting ip in 10.10.11.0 range but getting dns as 8.8.8.8 4.2..2.2

because of that i an not getting resolved internal network host name please help me out 

ip dhcp excluded-address 10.10.11.1 10.10.11.50
!
ip dhcp pool LAN_Pool
network 10.10.11.0 255.255.255.0
default-router 10.10.11.1
dns-server 192.168.1.1 192.168.1.2
lease 5

[shaikhaltamash291]

Hii Sir,

I have a cisco router in which i have configured a dhcp pool of 192.168.1.0 255.255.255.0 i have assigned 10 pc as 

static ip's . when i restart my router the dhcp pc gets dhcp ips but the static pc ip's not getting lived i have to manually do shut on shut

switch port or plug out/in cable. please suggest what would be the problem  

[shaikhaltamash291]

Dear sir

I have mistakenly erased the ios of cisco2950 24 port switch

switch is not booting now what need to be done i didnt have ios image also please share me the link of ios if possible

and how to load it on switch please help

[shaikhaltamash291]

Dear sir  ,

i want ur help

I have a mpls network 0f 59  branches i am sitting on a core router 2900

i want to block a server with ip 192.168.1.85 accessing for all branches excluding 10.10.9.0 network

and other branches ip ranges from 10.10.0.0 255.255.0.0 

i have applied th acceslist policy but its not working 

i have made two different polices and applied one by one

1)

access-list 110 deny ip any host 192.168.1.85
access-list 110 permit ip 10.10.9.0 0.0.0.255 host 192.168.1.85
access-list 110 permit ip any any

2)

access-list 120 permit ip host 192.168.1.85 10.10.9.0 0.0.0.255
access-list 120 deny ip host 192.168.1.85 any
access-list 120 permit ip any any

output

10 permit ip host 192.168.1.85 10.10.9.0 0.0.0.255 (288332 matches)
20 deny ip host 192.168.1.85 any (10011 matches)
30 permit ip any any (1960357 matches)

[Giuseppe Larosa]

Hello -shaika,

you need to make some changes to your ACLs to make them working:

1)  the first line of ACL 110 should be that allows access to the server from 10.10.9.0/24

access-list 110 permit ip host 192.168.1.85 10.10.9.0 0.0.0.255

access-list 110 deny ip host 192.168.1.85 10.10.0.0 0.0.255.255

access-list 110 permit ip 192.168.1.0 0.0.0.255 any

this has to be applied inbound (in direction ) on the interface that connects to the server on the central site router

2) ACL 120 looks like fine if you want to block access to the server 192.168.1.85 from anywhere except network 10.10.9.0/24. For security reasons called anti spoofing you should allow only traffic with a source that belongs to the IP subnet that is directly connected to your router interface. So ACL 120 line 3 should become

access-list 120 permit ip 192.168.1.0 0.0.0.255 any

The difference between ACL 110 and ACL 120 is that ACL 110 blocks communication between server 192.168.1.85 and all 10.10./16 branch subnets except 10.10.9.0/24 but allows also communication with external world.

Your version of ACL110 is wrong because the order of the ACL lines is important..

Your version of ACL 120 can work if applied inbound on the interface towards the server on the central router.

interface type x/y

ip access-group 120 in

!

Hope to help

Giuseppe