cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
Announcements
163
Views
0
Helpful
1
Replies
Highlighted
Beginner

What is the order of operations for NAT translation when a ping is sent out an interface?

I have two routers set up as below:

https://imgur.com/USLlHAQ

The 10.0.0.1 and 10.0.1.2 networks are configured as loopback interfaces.

Se0/1/0 on RouterA is configured with IP address 192.168.0.1 and Se0/2/0 on RouterB is configured with IP address 192.168.0.2.

I have the current nat configuration (no default routes set):

access-list 10 permit 10.0.0.0 0.0.255.255

ip nat pool mypool 192.168.0.1 192.168.0.254 netmask 255.255.0.0

ip nat inside source list 10 pool mypool

I can issue a ping to destination 192.168.0.2 from source 10.0.1.2 successfully.

I get "....." when issuing a ping to destination 192.168.0.1 from source 10.0.1.2:

Sending 5, 100-byte ICMP Echos to 192.168.0.1, timeout is 2 seconds: Packet sent with a source address of 10.0.1.2

NAT: s=10.0.1.2->192.168.0.2, d=192.168.0.1 [81]

.

NAT: s=10.0.1.2->192.168.0.2, d=192.168.0.1 [82]

.

NAT: s=10.0.1.2->192.168.0.2, d=192.168.0.1 [83]

.

NAT: s=10.0.1.2->192.168.0.2, d=192.168.0.1 [84]

.

NAT: s=10.0.1.2->192.168.0.2, d=192.168.0.1 [85]

.

Success rate is 0 percent (0/5)

Can someone clarify what the series of steps are that is preventing a successful ping?

1 ACCEPTED SOLUTION

Accepted Solutions
VIP Advisor

Re: What is the order of operations for NAT translation when a ping is sent out an interface?

Hello
Domain based nat does have a nat order of operation and as I understand it in summary

inside <> outside nat ,Translation is performed after route lookup and routing and as you don't have any default routes to forward traffic then after this translation the rtr has no define next-hop path to take that why its failing

outside <> inside nat,  its the reverse,  here route lookup, routing is before any translation

NAT Order of Operation



kind regards
Paul

Please rate and mark posts accordingly if you have found any of the information provided useful.
It will hopefully assist others with similar issues in the future
1 REPLY 1
VIP Advisor

Re: What is the order of operations for NAT translation when a ping is sent out an interface?

Hello
Domain based nat does have a nat order of operation and as I understand it in summary

inside <> outside nat ,Translation is performed after route lookup and routing and as you don't have any default routes to forward traffic then after this translation the rtr has no define next-hop path to take that why its failing

outside <> inside nat,  its the reverse,  here route lookup, routing is before any translation

NAT Order of Operation



kind regards
Paul

Please rate and mark posts accordingly if you have found any of the information provided useful.
It will hopefully assist others with similar issues in the future
CreatePlease to create content
Content for Community-Ad
July's Community Spotlight Awards