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Problem report
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Resolution: Fixed
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Major
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6.0.23rc1, 6.4.7, 7.0.0alpha7
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None
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Sprint 106 (Nov 2023)
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1
Steps to reproduce:
Our Cisco UCS manager sometimes generates empty replies to GetBulk requests. (error=0, index=0, varbind length=0). The poller reacts to this by sending the same request again. Resulting in a storm of requests&empty replies.
Result:
IP (tos 0x0, ttl 64, id 57012, offset 0, flags [none], proto UDP (17), length 80)
10.255.0.134.21437 > 10.14.90.105.161: { SNMPv2c C="xxxxx" { GetBulk(38) R=807747303 N=0 M=0 .1.3.6.1.4.1.9.9.719.1.1.1.1.20.8611890 } }
0x0000: 4500 0050 deb4 0000 4011 xxxx 0aff 0086 E..P....xxxx....
0x0010: 0a0e 5a69 53bd 00a1 003c xxxx 3032 0201 ..ZiS...xxxx02..
0x0020: 0104 05xx xxxx xxxx a526 0204 3025 3ee7 ...xxxxx.&..0%>.
0x0030: 0201 0002 0100 3018 3016 0612 2b06 0104 ......0.0...+...
0x0040: 0109 0985 4f01 0101 0114 848d d032 0500 ....O........2..
IP (tos 0x0, ttl 63, id 52275, offset 0, flags [none], proto UDP (17), length 56)
10.14.90.105.161 > 10.255.0.134.21437: { SNMPv2c C="xxxxx" { GetResponse(14) R=807747303 } }
0x0000: 4500 0038 cc33 0000 3f11 xxxx 0a0e 5a69 E..8.3..xxxx..Zi
0x0010: 0aff 0086 00a1 53bd 0024 xxxx 301a 0201 ......S.xxxx0...
0x0020: 0104 05xx xxxx xxxx a20e 0204 3025 3ee7 ...xxxxx....0%>.
0x0030: 0201 0002 0100 3000 ......0.
0x0028: a2 0e SNMP response, len=14
0x002a: 02 04 30253ee7 request id (int, len=4, 0x30253ee7)
0x0030: 02 01 00 error status (int, len=1, 0)
0x0033: 02 01 00 snmpIndex (int, len=1, 0)
0x0036: 30 00 varbindlist len=0
The above packets repeat several hundred times per second.
Expected:
I'm currently testing this patch:
--- checks_snmp.c.dist 2023-10-30 12:32:27.650772000 +0100 +++ checks_snmp.c 2023-10-30 12:34:11.120649000 +0100 @@ -1304,6 +1304,13 @@ goto next; } + if (NULL == response->variables) { + zbx_strlcpy(error, "received empty reply.", max_error_len); + ret = NOTSUPPORTED; + running = 0; + break; + } + /* process response */ for (num_vars = 0, var = response->variables; NULL != var; num_vars++, var = var->next_variable) {
(patch is against master)
- is duplicated by
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ZBX-23671 snmp flooding on cisco ios
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- Closed
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