Problems with snmpwalk

[tmeto]

We have installed the snmp agent on a remote machine (195.81.194.195:553 ) and we need to access it through our host where Nagios is located, the problem is that the snmpwalk does not work although it send snmp traps to the remote machine :

Nagios host:
snmpwalk -v 2c -c nagiosica 195.81.194.195:553

Remote host:
root@gnpt-glpi:/etc/snmp# tcpdump -i eth0 udp port 161
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
14:14:37.595923 IP 70.244.14.62.static.jazztel.es.45497 > ubuntu.snmp: C=nagiosica GetNextRequest(25)
14:14:38.596083 IP 70.244.14.62.static.jazztel.es.45497 > ubuntu.snmp: C=nagiosica GetNextRequest(25)
14:14:39.596940 IP 70.244.14.62.static.jazztel.es.45497 > ubuntu.snmp: C=nagiosica GetNextRequest(25)
14:14:40.598073 IP 70.244.14.62.static.jazztel.es.45497 > ubuntu.snmp: C=nagiosica GetNextRequest(25)
14:14:41.599094 IP 70.244.14.62.static.jazztel.es.45497 > ubuntu.snmp: C=nagiosica GetNextRequest(25)
14:14:42.599944 IP 70.244.14.62.static.jazztel.es.45497 > ubuntu.snmp: C=nagiosica GetNextRequest(25)

That could be happening?

Thanks so much

[hsmith]

Do you have port forwarding enabled? It looks like you're trying to walk port 553, but doing a tcpdump on 161.

[tmeto]

Do you have port forwarding enabled? It looks like you're trying to walk port 553, but doing a tcpdump on 161.

Yes, I confirm you that we have port 661 enabled (SNMP). We have made NAT to access this remote host by port 553 (the machine is 195.81.194.195:553 ) independently of port 661, so our machine remote the 195.81.194.195:553, but it does not work the snmpwalk command in the source device

[nozlaf]

looks like a NAT issue to me check your firewall logs

[hsmith]

Thanks @nozlaf!