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Internet for public LAN IP and Private WAN IP

titusroz03
Level 1
Level 1

HI All,

My ISP have provided the below config for a DIA circuit.

titusroz03_0-1736743338034.png

WAN Ips are private ones and LAN subnet is public(Subnets are hided in image for security)

I can reach the internet from the LAN public IP(ISP) provided from ISP if I have static route pointed to their WAN ip as below

titusroz03_1-1736743459810.png

But if I am trying to reach internet from my internal LAN ip(192.168.2.0/24) it's not working. I have NAT overload were my LAN ip(192.168.x.x) is insidelocal and LAN public IP provided from ISP as Insideglobal. Can any one provide suggestions to make this work..?

Do I need to make sure on routing of my internal LAN..?

 

1 Accepted Solution

Accepted Solutions

Devaa
Level 1
Level 1

I believe you should config something like this. Your outside interface will have private 10.x IP given by ISP, which makes sense with your default route. 

 

int g0/0/2.4
 ip add 10.104.150.210 255.255.255.252

 

Once you make the above change, try to ping 10.104.150.209 (if allowed from ISP side)

! Configure proper START IP (A) and End IP (B) and subnet mask as given by ISP

 

ip nat pool NAT-POOL 202.X.X.A 202.X.X.B netmask 255.255.255.0
ip nat inside source list 10 pool NAT-POOL overload

 

Above config should fix your issue. Let me know if you observe any issues. 

View solution in original post

9 Replies 9

Devaa
Level 1
Level 1

Could you please share inside interface, outside interface and NAT config (mask your public IP for security)?

Ip Nat Outside

titusroz03_0-1736747082125.png

IP Nat inside

titusroz03_1-1736747139682.png

NAT config

titusroz03_2-1736747188827.png

 

 

 

M02@rt37
VIP
VIP

Hello @titusroz03 

Please verify NAT translations using 

#show ip nat translations command

When you try "to reach internet" from you LAN.... you test with icmp or webpage?

 

Best regards
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NO nat Translations are viewed since it hits route first and nat next.

When you try "to reach internet" from you LAN.... you test with icmp or webpage?

Best regards
.ı|ı.ı|ı. If This Helps, Please Rate .ı|ı.ı|ı.

Yes...ICMP from router tested as below

titusroz03_0-1736752859500.png

 

Ok @titusroz03 

So please check your ACL #10. Ensure that this ACL match tou LAN Netwok.

Best regards
.ı|ı.ı|ı. If This Helps, Please Rate .ı|ı.ı|ı.

Devaa
Level 1
Level 1

I believe you should config something like this. Your outside interface will have private 10.x IP given by ISP, which makes sense with your default route. 

 

int g0/0/2.4
 ip add 10.104.150.210 255.255.255.252

 

Once you make the above change, try to ping 10.104.150.209 (if allowed from ISP side)

! Configure proper START IP (A) and End IP (B) and subnet mask as given by ISP

 

ip nat pool NAT-POOL 202.X.X.A 202.X.X.B netmask 255.255.255.0
ip nat inside source list 10 pool NAT-POOL overload

 

Above config should fix your issue. Let me know if you observe any issues. 

Thank you very much..It worked as expected

titusroz03_0-1736774448874.png

 

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