snmp server not receives data

Question

enter code hereI have a problem when using the snmp and the server receives data, The service is running correctly and the port is listening

I do a snmpwalk -v 2c -c mycommunity 192.168.1.82 (which is the same) and it answers me and a snmpwalk -v 2c -c mycommunity localhost and also, that is, the service is working but it does not respond from any machine other than her same a sudo netstat -tulpn | grep snmp sudo netstat -tulpn | grep snmp udp 0 0 0.0.0.0:161 0.0.0.0:* 15014/snmpd

something similar happened to someone?

Have you checked that there is no firewall avoiding external connections?, — J.M. Robles, Jan 15 '22 at 11:48
in iptables I do not see anything strange and the ping if it arrives — zapeador, Jan 17 '22 at 07:04
Could you share the output of iptables -L and nft list tables? — J.M. Robles, Jan 17 '22 at 16:21
it has many iptables rules and it won't let me put so much text here — zapeador, Jan 18 '22 at 07:28

J.M. Robles · Answer 1 · 2022-01-18T16:54:35.157

If firewalls are not involved, probably your configuration of the SNMPD service only accepts queries from local addresses.

Please, change the configuration of agentadress in /etc/snmp/snmpd.conf to

agentaddress udp:161

EDIT

If I am not wrong, your iptables configuration is establishing the DROP policy (anyway, the last rule is REJECT), so, you must allow explicitly all the traffic you want to reach your processes. In this case, the incoming traffic to port 161

iptables -A INPUT -p udp --dport 161 -j ACCEPT

If that works, you shuld make the rule persistent. Please find where the iptables rules are saved (/etc/iptables/rules.v4 ?) and edit to add the rule

I already have that line like this in the configuration file — zapeador, Jan 18 '22 at 07:20

score 0 · Accepted Answer · answered Jan 21 '22 at 11:17

0

finally it was an iptables issue that in its last line of input had a REJECT all the only thing I had to do was insert the rule above the REJECT with a:

iptables -I INPUT 23 -p udp --dport 161 -j ACCEPT

I put it here in case someone cares

answered Jan 21 '22 at 11:17

zapeador

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snmp server not receives data

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