topic Re: ASA5515 ERROR: NAT unable to reserve ports in Network Security

ASA5515 ERROR: NAT unable to reserve ports

Qays — Tue, 18 May 2021 13:11:05 GMT

I have an SNMP server for monitoring and I want to allow outside interface devices to connect to the server, while I am creating static nat I get this error (ERROR: NAT unable to reserve ports).

the used commands:

ASA(config)# object network Zabbix
ASA(config-network-object)# host 10.10.10.50
ASA(config-network-object)#
ASA(config-network-object)# nat (INSIDE,OUTSIDE) static interface service udp 161 161
ERROR: NAT unable to reserve ports.

any idea about this situation, please??

Re: ASA5515 ERROR: NAT unable to reserve ports

balaji.bandi — Tue, 18 May 2021 13:25:20 GMT

if the port 161 already used locally with ASA you may not do i guess here : change from 161 to custom port.

Look at the example of thread :

https://community.cisco.com/t5/network-security/error-nat-unable-to-reserve-ports-https/td-p/2946131

Re: ASA5515 ERROR: NAT unable to reserve ports

Qays — Tue, 18 May 2021 13:50:58 GMT

could I change the default port number for SNMP from the default value?

my remote device is a cisco router and I couldn't find any way to specify the port number for SNMP connections

Re: ASA5515 ERROR: NAT unable to reserve ports

balaji.bandi — Tue, 18 May 2021 14:39:22 GMT

outside you can use any port to coming

From outside you 1161 port and you can to NAT to Internal IP 161

make sure you SNMP to 1161 port - should work as expected.

example :

nat (INSIDE,OUTSIDE) static interface service udp 161 1161

Re: ASA5515 ERROR: NAT unable to reserve ports

Qays — Mon, 24 May 2021 10:21:54 GMT

Hi balaji.bandi

sorry for the late response
my problem here that the router will generate the traffic using port 161 it is the default port for SNMP

so this will not work for me

Thanks