04-02-2022 07:10 PM
I have configured R2 router NAT:
R2(config)#ip route 0.0.0.0 0.0.0.0 s1/0
R2(config)#access-list 10 permit 172.8.55.0 0.0.0.255
R2(config)#ip nat inside source list 10 interface s1/0 overload
R2(config)#int s1/0
R2(config-if)#ip nat outside
R2(config-if)#int f0/1
R2(config-ig)#ip nat inside
My router R2 has OSPF configured with 2 other routers before, they are in zone 172.8.55.0/24.
When I configure NAT but I can't ping from inside NAT (R2) to outside (PC1)?
Help me, please
04-03-2022 08:35 PM
I don't think R2 know all route. I can ping from VLAN10 to VLAN20 but I can't ping from PC6 to R2
R2#sh ip access-lists
Standard IP access list 10
10 permit 172.8.55.0, wildcard bits 0.0.0.255
R2#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is 0.0.0.0 to network 0.0.0.0
172.8.0.0/24 is subnetted, 1 subnets
C 172.8.55.0 is directly connected, FastEthernet0/1
11.0.0.0/30 is subnetted, 1 subnets
C 11.0.0.0 is directly connected, Serial1/0
S* 0.0.0.0/0 is directly connected, Serial1/0
04-03-2022 10:49 PM
In R2
Ping pc source 172.8.55.x
Do debug ip nat
You will get ping success.
For ospf still not get any in routing table?
Can i see show ip route in R1.
04-04-2022 01:13 AM
R1#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route
Gateway of last resort is not set
172.8.0.0/24 is subnetted, 1 subnets
C 172.8.55.0 is directly connected, FastEthernet0/1
172.10.0.0/24 is subnetted, 1 subnets
C 172.10.55.0 is directly connected, FastEthernet0/0.10
172.20.0.0/24 is subnetted, 1 subnets
C 172.20.55.0 is directly connected, FastEthernet0/0.20
R1#sh ip ospf nei
Neighbor ID Pri State Dead Time Address Interface
172.8.55.2 1 FULL/DROTHER 00:00:31 172.8.55.2 FastEthernet0/1
172.30.55.1 1 FULL/DR 00:00:31 172.8.55.3 FastEthernet0/1
04-04-2022 01:14 AM
I can't ping from PC6 to R2.
04-04-2022 01:39 AM
should I configure NAT at R1 so that PC6 can ping to R2?
04-04-2022 03:25 AM
First,
ping pc1 source 172.8.55.2 <<- this should work
Second still if there is no reachability then the ping will failed.
now why ospf not exchange update between router ?
Are you apply any acl in R2 172.8.55.2 interface?
04-04-2022 07:56 AM
One of the issues is that R1 does not have any default route. So it can only forward traffic to subnets that are in its routing table. Especially for forwarding traffic toward outside it will need a default route. It could be a static default on F1 or it could be a default advertised by an OSPF neighbor (which is probably the better alternative).
You ask "should I configure NAT at R1 so that PC6 can ping to R2?" Between R1 and R2 there is no need for NAT. You need NAT when you are attempting to get access outside your private network. You need NAT on R2 (and have at least part of what you need configured on R2).
04-04-2022 01:43 PM
Make sure ISP also run OSPF.
04-02-2022 11:29 PM - edited 04-02-2022 11:30 PM
Hello
Do you have full reachablity from your internal network to R2 1.1.1.x/30 if so, then the issue is your NAT.
Also post the packet tracer file if possible.
Basic nat would be:
int ser1/0
ip nat outside
int fa0/1
ip nat inside
ip access-list extended NAT
permit ip 172.8.55.0 0.0.0.255 any
ip nat inside source-list NAT interface serial 1/0
04-03-2022 08:41 PM - edited 04-03-2022 08:42 PM
A
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