[Pkg-net-snmp-devel] Bug#717179: Cannot snmpwalk snmpd using ipv6

[Neil Watson]

Package: snmpd
Version: 5.4.3~dfsg-2.7
Severity: important
Tags: ipv6

Dear Maintainer,
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-- System Information:
Debian Release: 7.1
   APT prefers stable
   APT policy: (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 3.2.0-4-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_CA.UTF-8, LC_CTYPE=en_CA.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash


Snmpwalk to an ipv6 address is failing. I have a host configured with a
global ipv6 address. Snmpd is listening on ipv6.

netstat -l|grep snmp
udp        0      0 localhost:snmp          *:*
udp6       0      0 [::]:snmp               [::]:*
udp6       0      0 [::]:snmp-trap          [::]:*

Snmpwalk, on the same host, is failing.

snmpwalk -v2c -c public udp6:[::1] system
Timeout: No Response from udp6:[::1]

snmpwalk -v2c -c public 'udp:localhost' system
SNMPv2-MIB::sysDescr.0 = STRING: Linux scope 3.2.0-4-amd64 #1 SMP
Debian 3.2.46-1 x86_64
SNMPv2-MIB::sysObjectID.0 = OID: NET-SNMP-MIB::netSnmpAgentOIDs.10
DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (54775) 0:09:07.75
... etc

snmpd.conf

agentAddress  udp6:161,udp:localhost:161
syslocation  home
syscontact  neil at example.com
rocommunity  public
disk  / 5000kB

snmpd shows a connection in syslog.

Jul 16 22:25:41 scope snmpd[11066]: Connection from UDP/IPv6:
[2604:xxxx:100:8111::3]:53063
Jul 16 22:25:42 scope snmpd[11066]: Connection from UDP/IPv6:
[2604:xxxx:100:8111::3]:53063
Jul 16 22:25:43 scope snmpd[11066]: Connection from UDP/IPv6:
[2604:xxxx:100:8111::3]:53063

tcpdump for ipv4 walk:
10:05:30.657805 IP localhost.snmp > localhost.36209:  C=public GetResponse(31)  system.9.1.4.8=1
10:05:30.658566 IP localhost.36209 > localhost.snmp:  C=public GetNextRequest(30)  system.9.1.4.8
10:05:30.659327 IP localhost.snmp > localhost.36209:  C=public GetResponse(29)  interfaces.ifNumber.0=2

tcpdump for ipv6 walk:
10:05:41.695112 IP6 2604:xxxx:100:8111::3.42476 > 2604:xxxx:100:8111::3.snmp:  C=public GetNextRequest(26)  system
10:05:42.697798 IP6 2604:xxxx:100:8111::3.42476 > 2604:xxxx:100:8111::3.snmp:  C=public GetNextRequest(26)  system
10:05:43.699182 IP6 2604:xxxx:100:8111::3.42476 > 2604:xxxx:100:8111::3.snmp:  C=public GetNextRequest(26)  system

-- 
Neil Watson
Linux/UNIX Consultant
http://watson-wilson.ca