09-02-2021 11:05 PM
Hello my friends,
i need one help on facing one issue on cisco ISR4431 Router Configuration, i am using DHCP ISP in 0/0/0 GigabiteEther port 192.168.*.* as DHCP. and GigabitEthernet 0/0/1 i am using 192.168.2.1 Static IP address for internal network, here problem is i am not able ping ISP default Gateway 192.168.1.1 IP address from Gigabit Ethernet port 0/0/1, refer below code for which i am configuring.
Router#show ip interface brief
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0/0 192.168.1.4 YES DHCP up up
GigabitEthernet0/0/1 unassigned YES unset administratively down down
GigabitEthernet0/0/2 unassigned YES unset administratively down down
GigabitEthernet0/0/3 unassigned YES unset administratively down down
GigabitEthernet0 unassigned YES unset administratively down down
=> Below command i have configured as a dhcp in GigabitEthernet 0/0/0.refer below:
Router#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#interface gigabitEthernet0/0/0
Router(config-if)#no shutdown
Router(config-if)#ip address dhcp
=> after this dhcp configuration i am trying to ping 192.168.1.1 but its not pinging as well.
Router(config)#do ping 192.168.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.1, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
=> Then i have configured GigabitEthernet 0/0/1 for internal network, refer command below:
TPNODL-CENTRAL-STORE(config)#interface gigabitEthernet 0/0/1
TPNODL-CENTRAL-STORE(config-if)#ip address 192.168.2.1 255.255.255.0
TPNODL-CENTRAL-STORE(config-if)#no shutdown
TPNODL-CENTRAL-STORE(config-if)#exit
=> then i checked the interfacebrief command to see the interface, refer below:
TPNODL-CENTRAL-STORE#show ip interface brief
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0/0 192.168.1.4 YES DHCP up up
GigabitEthernet0/0/1 192.168.2.1 YES manual up up
GigabitEthernet0/0/2 unassigned YES unset administratively down down
GigabitEthernet0/0/3 unassigned YES unset administratively down down
GigabitEthernet0 unassigned YES unset administratively down down
Both the GigabitEthernet 0/0/0 is up but still i am not able ping ISP Default gateway 192.168.1.1 from GigabitEthernet 0/0/1 but i am able to ping the GigabitEthernet 0/0/0 DHCP ip from GigabietEthernet 0/0/1 Port.
=> after this i have created the DHCP pool for our internal network and provided ip route as well
TPNODL-CENTRAL-STORE(config)#ip dhcp pool centralstore
TPNODL-CENTRAL-STORE(dhcp-config)#network 192.168.2.0 /24
TPNODL-CENTRAL-STORE(dhcp-config)#default-router 192.168.2.1
TPNODL-CENTRAL-STORE(dhcp-config)#dns-server 8.8.8.8 4.2.2.2
TPNODL-CENTRAL-STORE(dhcp-config)#exit
TPNODL-CENTRAL-STORE(config)#ip route 0.0.0.0 0.0.0.0 192.168.1.1
TPNODL-CENTRAL-STORE(config)#exit
=> after this command still try to ping the ISP Gateway still it is not pinging. then i have configured Inside NAT and Outside Nat Command below
TPNODL-CENTRAL-STORE(config)#interface gigabitEthernet 0/0/0
TPNODL-CENTRAL-STORE(config-if)#ip nat outside
TPNODL-CENTRAL-STORE(config-if)#exit
TPNODL-CENTRAL-STORE(config)#interface gigabitEthernet 0/0/1
TPNODL-CENTRAL-STORE(config-if)#ip nat inside
TPNODL-CENTRAL-STORE(config-if)#exit
=> after that i have created the access list then overload with GigabitEthernet 0/0/0,
TPNODL-CENTRAL-STORE(config)#ip access-list standard 1
TPNODL-CENTRAL-STORE(config-std-nacl)#permit any
TPNODL-CENTRAL-STORE(config-std-nacl)#exit
TPNODL-CENTRAL-STORE(config)#ip nat in
TPNODL-CENTRAL-STORE(config)#ip nat inside sou
TPNODL-CENTRAL-STORE(config)#ip nat inside source list 1 int
TPNODL-CENTRAL-STORE(config)#ip nat inside source list 1 interface gigabitEthernet 0/0/0 overload
TPNODL-CENTRAL-STORE(config)#exit
after this overload command i am able to access internet connection but before this overload command i am not able to ping 192.168.1.1 ISP default gateway.
after this i am saving all the configuration using below command.
TPNODL-CENTRAL-STORE#copy running-config startup-config
Destination filename [startup-config]?
Building configuration...
[OK]
TPNODL-CENTRAL-STORE#
*Sep 1 16:10:11.126: %SYS-2-PRIVCFG_ENCRYPT: Successfully encrypted private config file
But also when we restrarted the router again, the DHCP is showing unasigned and internet is not access in the internal network. getting below code when using interface brief command
TPNODL-CENTRAL-STORE#show ip interface brief
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0/0 unassigned YES DHCP up up
GigabitEthernet0/0/1 192.168.2.1 YES manual up up
GigabitEthernet0/0/2 unassigned YES unset administratively down down
GigabitEthernet0/0/3 unassigned YES unset administratively down down
GigabitEthernet0 unassigned YES unset administratively down down
i request you to help me out on this as soon as possible and thanks in advance for your help guys.
09-02-2021 11:44 PM
Hello,
a NAT access list with 'permit any' does not work. Make sure the access list looks like below:
access-list 1 permit 192.168.2.0 0.0.0.255
Also, do you have a default route ?
ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/0/0 dhcp
?
09-02-2021 11:50 PM
Yes, for ISP it is 192.168.1.1 is default gateway
09-02-2021 11:46 PM - edited 09-03-2021 12:58 AM
worth posting show run after saving verify here :
here are some suggestions :
ip dhcp excluded-address 192.168.2.1
!access-list 1permit ip 192.168.2.0 0.0.0.255 any
access-list 1 permit 192.168.2.0 0.0.0.255
!
ip route 0.0.0.0 0.0.0.0 GigabitEthernet 0/0/0 dhcp
still not working as suggested post-show run
@Georg Pauwen ..appologies, corrected now.
09-02-2021 11:48 PM
Yes, for ISP it is 192.168.1.1 is default gateway
09-03-2021 12:58 AM
i would use interface with DHCP, since it is DHCP to get route.
09-02-2021 11:53 PM
--> access-list 1 permit ip 192.168.2.0 0.0.0.255 any
Not to be annoying but this is the wrong syntax...
09-03-2021 03:23 AM - edited 09-03-2021 03:24 AM
Hello
can you post
show version?
In addtion try the follwoing:
conf t
no service private-config-encryption
default int gig0/0/0
default int gig0/0/1
do wr mem
reload
int gig0/0/0
ip address dhcp
ip nat outside
no shut
int gig0/0/1
ip address 192.168.2.1 255.255.255.0
ip nat inside
no shut
access-list 100 permit ip 192.168.2.0 0.0.0.255 any
ip nat inside source-list 100 interface gig0/0/0
sh ip int brief | in up
sh ip route
ip route 0.0.0.0 0.0.0.0 gig0/0/0 dhcp
wr mem
reload
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide