nat failing iosv - no output from sh ip nat translations

[OscarChacon]

My configuration seems to be ok, but NAT is failing from 10.10.1.1/24 network.

Here is my NAT config

ip access-list 10 permit 10.0.0.0 0.0.255.255

interface e1/0
ip address 172.16.1.2 255.255.255.0
ip nat outside

interface e1/1
ip nat inside

int loopback 25
ip address 172.16.16.16 255.255.255.0

ip nat inside source list 10 interface Loopback25 overload

I'm running a test ping but not getting anything on the 'show ip nat translations'

[alan_schneider · Accepted solution]

your problem is the wildcard mask on the access-list. You should change it to 0.255.255.255 if you want to match 10.10.1.1/24 network.
ip access-list 10 permit 10.0.0.0 0.0.255.255 <- this only matches 10.0.x.x it won't match 10.10.1.X

[OscarChacon]

Thanks. I don't know how I missed that. 

[Georg Pauwen]

Hello,

on a side note:

--> your problem is the wildcard mask on the access-list. You should change it to 0.255.255.255 if you want to match 10.10.1.1/24 network.

Shouldn't the wildcard mask be 0.0.0.255 then ? 0.255.255.255 would only match 10.0.0.0.

Either way, the access list should be:

ip access-list 10 permit 10.0.0.0 0.0.0.255

[alan_schneider]

His ip was 10.10.1.1/24. 

0.255.255.255 would match the entire 10.0.0.0/8 <-10.10.x.x matched

0.0.0.255 would only match 10.0.0.0/24 <- 10.10.x.x not matched

[Georg Pauwen]

Hello,

you are right. I guess what I wanted to point out is that the match should be as close as possible.

10.10.1.1/24

should translate to:

ip access-list 10 permit 10.10.1.0 0.0.0.255

Yours (10.0.0.0 0.255.255.255) would match as well, but it includes the entire class A network.