排除ASR 5000/5500上的基礎設施客戶端DNS故障
目錄
簡介
本文說明如何排解與網域名稱服務(DNS)基礎架構相關的問題。其中包括各種命令列介面(CLI)、DNS概念以及可能需要收集的其他資料。根據需要提供示例輸出，以便更好地解釋某些點。
思科聚合服務路由器(ASR)5000/5500上的基礎設施DNS負責在配置它的上下文中解析完全限定域名(FQDN)。這通常是為了在入口上下文中支援呼叫控制的各個方面。 例如：
- 任何採用FQDN格式而不是IP地址的Diameter端點對等體的解析度
- 使用者裝置(UE)需要的Diameter S6b響應中返回的代理呼叫會話控制功能(P-CSCF)FQDN的分解，以便向IP多媒體系統(IIMS)核心註冊
- 高速封包資料服務閘道(HSGW)需要進行DNS命名應用命名授權指標(NAPTR)查詢，以取得要連線到的封包資料網路閘道(PGW)清單（新增或交接），然後進行DNS AAAA查詢，以擷取PGW本機行動錨點(LMA)位址的IP位址以連線呼叫。
- 移動性管理實體(MME)需要進行DNS NAPTR查詢，以獲取要連線的服務網關(SGW)/PGW對清單。這包括建立DNS AAAA/A查詢以檢索這些節點的IP。
組態
DNS作為客戶端應用程式在需要它的環境中實施非常簡單。以下是此類實作的範例：
context ingress
ip name-servers 2001:5555:202:fffe:a0:e:0:3 2001:5555:203:fffe:c0:e:0:3
dns-client HSGW-DNS
bind address 2001:5555:200:1011:342:281::
resolver retransmission-interval 2
resolver number-of-retries 3
exit
exit
要配置的最小值是服務/繫結地址和主（或輔助）DNS伺服器地址。
UDP與TCP
讓DNS變得更為複雜的是傳輸層。雖然DNS查詢通常基於UDP，但基於請求的NAPTR查詢最終可能會基於TCP。原因在於UDP的回應大小有限制，這要求TCP透過多個封包傳輸回應。封包流程包含初始要求，然後是來自DNS伺服器的回應。這會導致透過0負載回應透過TCP重新要求，且已設定TrunCated(TC)旗標。這表示根據RFC 5966，使用者端應以TCP/IP的身份重試。接著進行典型的TCP三向交換，然後是第二次請求。什麼時候大小足以要求此功能？例如，在HSGW的情況下，如果請求為切換，則UDP應該足夠多，因為只有一個或多個網關FQDN（如果返回多個服務）才能HSGW連線。但對於新呼叫，可返回的所有網路範圍內可能的PGW清單可能足夠長，需要使用TCP方法。
以下是請求TCP的回應（來自Wireshark）範例：
Frame 85: 143 bytes on wire (1144 bits), 143 bytes captured (1144 bits)
Ethernet II, Src: JuniperN_20:e7:f0 (64:87:88:20:e7:f0), Dst:
StarentN_02:b1:9d (00:05:47:02:b1:9d)
802.1Q Virtual LAN, PRI: 0, CFI: 0, ID: 2010
Internet Protocol Version 6, Src: 2001:5555:202:fffe:a0:e:0:3
(2001:5555:202:fffe:a0:e:0:3), Dst: 2001:5555:200:1011:304:281::
(2001:5555:200:1011:304:281::) User Datagram Protocol, Src Port: domain (53),
Dst Port: 35049 (35049)
Domain Name System (response)
[Request In: 81]
[Time: 0.088530870 seconds]
Transaction ID: 0x3b2b
Flags: 0x8780 Standard query response, No error
1... .... .... .... = Response: Message is a response
.000 0... .... .... = Opcode: Standard query (0)
.... .1.. .... .... = Authoritative: Server is an authority for domain
.... ..1. .... .... = Truncated: Message is truncated
.... ...1 .... .... = Recursion desired: Do query recursively
.... .... 1... .... = Recursion available: Server can do recursive queries
.... .... .0.. .... = Z: reserved (0)
.... .... ..0. .... = Answer authenticated: Answer/authority portion
was not authenticated by the server
.... .... ...0 .... = Non-authenticated data: Unacceptable
.... .... .... 0000 = Reply code: No error (0)
Questions: 1
Answer RRs: 0
Authority RRs: 0
Additional RRs: 1
Queries
APN1.apn.epc.mnc420.mcc300.3gppnetwork.org: type NAPTR, class IN
Name: APN1.apn.epc.mnc420.mcc300.3gppnetwork.org
Type: NAPTR (Naming authority pointer)
Class: IN (0x0001)
Additional records
疑難排解指令
show dns-client statistics client <DNS Client Name>
這是用於排除DNS問題的主要命令。以下為運行此命令的一些亮點：
- 它必須在定義客戶端的上下文中運行。
- 多次運行它並記錄相關統計資訊（如超時）中的增加情況。
- 使用情況統計資訊統計實際呼叫成功/失敗的數量，這些成功或失敗是由於能夠/不能解析DNS造成的。
- DNS解析程式統計故障計數超時次數，以及連線被拒絕等其它故障。超時可能是由於TCP連線建立問題。
- 根據這些統計資訊，使用SNMP陷阱（和警報）ThreshDNSLookupFailure捕獲DNS故障配置閾值。示例: threshold dns-lookup-failure 5 clear 5。
- 如果主裝置失敗，輔助裝置將在約2秒後嘗試運行（不可配置）。
- 方案CONTEXTSch1和CONTEXTSch2中的bulkstat變數包含與此命令相關的所有相關DNS基礎結構變數。NAPTR查詢型別的示例包括這些型別，它們也適用於AAAA和A型別查詢：
- dns-primary-ns-naptr-atmpts
- dns-primary-ns-naptr-fails
- dns-primary-ns-naptr-sucps
- dns-secondary-ns-naptr-atmpts
- dns-secondary-ns-naptr-fails
- dns-secondary-ns-query-timeouts
在此示例輸出中，請注意主伺服器和輔助伺服器的使用量和解析程式統計資訊中反映的NAPTR故障增加情況（完全中斷）：
[Ingress]HSGW> show dns-client statistics client HSGW-DNS
Monday June 02 00:26:29 UTC 2014
DNS Usage Statistics:
---------------------
Query Type Attempts Successes Failures
A 21802 0 21802
SRV 0 0 0
AAAA 3934082666 3934060659 21831
NAPTR 1393765619 1387607858 6156730
PTR 0 0 0
Total 1032902791 1026701221 6200363
DNS Cache Statistics:
---------------------
Total Cache Hits Cache Hits Not Found Hit Ratio
Lookups (Positive (Negative in Cache (Percentage)
Response) Response)
----------------------------------------------------------------------------
Central Cache: 94085256 89157603 6114 4921539 94.77%
Local Cache: 1032902770 926126458 20175 106756137 89.66%
DNS Resolver Statistics:
------------------------
Primary Name Server : 2001:5555:202:fffe:a0:e:0:3
Query Type Attempts Successes Failures
A 0 0 0
SRV 0 0 0
AAAA 66 64 2
NAPTR 746 37 709
PTR 0 0 0
Total Resolver Queries: 812
Successful Queries: 101
Query Timeouts: 705
Domain Not Found: 1
Connection Refused: 0
Other Failures: 5
Secondary Name Server : 2001:5555:203:fffe:c0:e:0:3
Query Type Attempts Successes Failures
A 0 0 0
SRV 0 0 0
AAAA 0 0 0
NAPTR 705 0 703
PTR 0 0 0
Total Resolver Queries: 705
Successful Queries: 0
Query Timeouts: 703
Domain Not Found: 0
Connection Refused: 0
Other Failures: 0
---------------------------------------------------
[Ingress]HSGW> show dns-client statistics client HSGW-DNS
Monday June 02 00:32:00 UTC 2014
DNS Usage Statistics:
---------------------
Query Type Attempts Successes Failures
A 21802 0 21802
SRV 0 0 0
AAAA 3934232613 3934210617 21831
NAPTR 1393923407 1387654707 6267989
PTR 0 0 0
Total 1033210526 1026898028 6320622
DNS Cache Statistics:
---------------------
Total Cache Hits Cache Hits Not Found Hit Ratio
Lookups (Positive (Negative in Cache (Percentage)
Response) Response)
----------------------------------------------------------------------------
Central Cache: 94120194 89157771 6114 4956309 94.73%
Local Cache: 1033210498 926323077 20175 106867246 89.66%
DNS Resolver Statistics:
------------------------
Primary Name Server : 2001:5555:202:fffe:a0:e:0:3
Query Type Attempts Successes Failures
A 0 0 0
SRV 0 0 0
AAAA 66 64 2
NAPTR 913 38 873
PTR 0 0 0
Total Resolver Queries: 979
Successful Queries: 102
Query Timeouts: 869
Domain Not Found: 1
Connection Refused: 0
Other Failures: 5
Secondary Name Server : 2001:5555:203:fffe:c0:e:0:3
Query Type Attempts Successes Failures
A 0 0 0
SRV 0 0 0
AAAA 0 0 0
NAPTR 869 0 869
PTR 0 0 0
Total Resolver Queries: 869
Successful Queries: 0
Query Timeouts: 869
Domain Not Found: 0
Connection Refused: 0
Other Failures: 0
show dns-client cache client <client name> [query-name <query-name>
[query-type <NAPTR | AAAA | A>] | [query-type <NAPTR | AAAA | A>]]
此命令報告快取中針對各種查詢型別的所有已儲存響應（尚未過期），包括A、AAAA和NAPTR。這給出了快取記憶體的當前狀態，從中可以得出關於是否會出現基於缺少條目的呼叫失敗的結論：
如果沒有任何限定符，則顯示整個快取記憶體，其數量可能超出您打算進行故障排除所需的數量。快取條目具有生存時間(TTL)，因此，所返回的條目僅在各個TTL也保留的情況下才適用。當您比較所有條目時，TTL可能不同，因此條目會在不同的時間過期。這是意料之中的。
選擇特定查詢型別（如NAPTR），並查詢應用點名稱(APN)結果或特定FQDN（切換）結果。需要查詢的內容包括缺少的特定APN、缺少所有APN或缺少切換結果。
範例：
此輸出顯示APN1和APN2的快取中一些條目，這些條目對於這些APN的新呼叫可能需要。實際清單包括每個可能的APN的每個可能的PGW的條目，在整個服務提供商的網路中，LTE(x-S5-gtp)和eHRPD(x-s2a-pmip)都包括在內。此處僅與x-s2a-pmip相關，因為這是需要通過S2a連線連線到PGW的HSGW。請注意同時從DNS伺服器返回的具有相同APN/PGW位置的條目的相同TTL(1307、631)，而應用於不同APN/PGW位置的條目的不同TTL（1307與631）則不同。
[Ingress]HSGW> show dns-client cache client HSGW-DNS
Monday June 02 00:26:59 UTC 2014
Query Name: so01.APN1.apn.epc.mnc485.mcc320.3gppnetwork.org
Query Type: NAPTR TTL: 1307 seconds
Answer:
Order: 100 Preference: 50000
Flags: a Service: x-3gpp-pgw:x-s5-gtp
Regular Expression:
Replacement: topon.lb1.pgw01.NYNY.sa008.so.node.epc.mnc485.mcc320.3gppnetwork.org
Query Name: so01.APN1.apn.epc.mnc485.mcc320.3gppnetwork.org
Query Type: NAPTR TTL: 1307 seconds
Answer:
Order: 100 Preference: 50000
Flags: a Service: x-3gpp-pgw:x-s2a-pmip
Regular Expression:
Replacement: topon.lb2.pgw01.NYNY.sa008.so.node.epc.mnc485.mcc320.3gppnetwork.org
Query Name: APN2.apn.epc.mnc485.mcc320.3gppnetwork.org
Query Type: NAPTR TTL: 631 seconds
Answer:
Order: 100 Preference: 50000
Flags: a Service: x-3gpp-pgw:x-s2a-pmip
Regular Expression:
Replacement: topon.lb2.pgw01.BOMA.sa001.mw.node.epc.mnc485.mcc320.3gppnetwork.org
Query Name: APN2.apn.epc.mnc485.mcc320.3gppnetwork.org
Query Type: NAPTR TTL: 631 seconds
Answer:
Order: 100 Preference: 50000
Flags: a Service: x-3gpp-pgw:x-s5-gtp
Regular Expression:
Replacement: topon.lb1.pgw01.BOMA.sa001.mw.node.epc.mnc485.mcc320.3gppnetwork.org
在此第二個輸出範例中，是從長期演化(LTE)切換到eHRPD所需的NAPTR專案，如特定PGW FQDN位置專案(pgw01.PHLA.xxxxxx)所示。與先前的輸出類似，使用的相關條目是服務= x-s2a-pmip的條目。請為同時返回的所有這些條目注意相同的TTL(515)。唯一的區別是服務。AAAA條目解析表示PGW LMA服務地址的s2a條目，以便後續的代理MIPv6請求可以傳送到PGW以繼續呼叫建立。
Query Name: pgw01.PHLA.sa004.mw.node.epc.mnc485.mcc320.3gppnetwork.org
Query Type: NAPTR TTL: 515 seconds
Answer:
Order: 100 Preference: 50000
Flags: a Service: x-3gpp-pgw:x-s2b-gtp
Regular Expression:
Replacement: topon.lb4.pgw01.PHLA.sa004.mw.node.epc.mnc485.mcc320.3gppnetwork.org
Query Name: pgw01.PHLA.sa004.mw.node.epc.mnc485.mcc320.3gppnetwork.org
Query Type: NAPTR TTL: 515 seconds
Answer:
Order: 100 Preference: 50000
Flags: a Service: x-3gpp-pgw:x-s2a-pmip
Regular Expression:
Replacement: topon.lb2.pgw01.PHLA.sa004.mw.node.epc.mnc485.mcc320.3gppnetwork.org
Query Name: pgw01.PHLA.sa004.mw.node.epc.mnc485.mcc320.3gppnetwork.org
Query Type: NAPTR TTL: 515 seconds
Answer:
Order: 100 Preference: 50000
Flags: a Service: x-3gpp-pgw:x-s5-gtp
Regular Expression:
Replacement: topon.lb1.pgw01.PHLA.sa004.mw.node.epc.mnc485.mcc320.3gppnetwork.org
Query Name: topon.lb2.pgw01.PHLA.sa004.mw.node.epc.mnc485.mcc320.3gppnetwork.org
Query Type: AAAA TTL: 646 seconds
Answer:
IPv6 Address: 2001:5555:200:1000:304:200::
dns-client query client-name <client name> query-type <NAPTR | AAAA> [query-name <query name>]
這是一個手動測試命令，用於啟動DSN客戶端，以便立即檢查快取並在存在快取時報告答案。否則，它會嘗試查詢並報告結果。如果查詢字串非常複雜，請確保其拼寫正確：
- 預設情況下，如果僅指定query-name，則客戶端假定查詢型別= A，因此NAPTR和AAAA請求需要查詢型別。
- 此處的結果與使用show dns-client cache查詢快取時返回的結果相同。例外情況是，如果查詢的內容不在快取中，則結果具有全新TTL。但是，如果已經存在於快取中，則TTL在新查詢中返回的值與0之間具有一些值。
示例（與上一輸出中的查詢相同）：
[Ingress]HSGW> dns-client query client-name HSGW-DNS query-type NAPTR
query-name pgw01.PHLA.sa004.mw.node.epc.mnc420.mcc300.3gppnetwork.org
Query Name: pgw01.PHLA.sa004.mw.node.epc.mnc420.mcc300.3gppnetwork.org
Query Type: NAPTR TTL: 188 seconds
Answer:
Order: 100 Preference: 50000
Flags: a Service: x-3gpp-pgw:x-s5-gtp
Regular Expression:
Replacement: topon.lb1.pgw01.PHLA.sa004.mw.node.epc.mnc420.mcc300.3gppnetwork.org
Query Name: pgw01.PHLA.sa004.mw.node.epc.mnc420.mcc300.3gppnetwork.org
Query Type: NAPTR TTL: 188 seconds
Answer:
Order: 100 Preference: 50000
Flags: a Service: x-3gpp-pgw:x-s2b-gtp
Regular Expression:
Replacement: topon.lb4.pgw01.PHLA.sa004.mw.node.epc.mnc420.mcc300.3gppnetwork.org
Query Name: pgw01.PHLA.sa004.mw.node.epc.mnc420.mcc300.3gppnetwork.org
Query Type: NAPTR TTL: 188 seconds
Answer:
Order: 100 Preference: 50000
Flags: a Service: x-3gpp-pgw:x-s2a-pmip
Regular Expression:
Replacement: topon.lb2.pgw01.PHLA.sa004.mw.node.epc.mnc420.mcc300.3gppnetwork.org
[Ingress]HSGW> dns-client query client-name HSGW-DNS query-type AAAA
query-name topon.lb2.pgw01.PHLA.sa004.mw.node.epc.mnc420.mcc300.3gppnetwork.org
Query Name: topon.lb2.pgw01.PHLA.sa004.mw.node.epc.mnc420.mcc300.3gppnetwork.org
Query Type: AAAA TTL: 117 seconds
Answer:
IPv6 Address: 2001:5555:200:1000:304:200::
此輸出顯示了基於TCP的查詢失敗的示例。您只能從查詢本身得知這是基於TCP的，但是您知道基於APN的NAPTR查詢響應對於UDP而言過大。
[Ingress]HSW> dns-client query client-name HSGW-DNS query-type NAPTR
query-name APN1.apn.epc.mnc420.mcc300.3gppnetwork.org
Query Name: APN1.apn.epc.mnc420.mcc300.3gppnetwork.org
Query Type: NAPTR TTL: 0 seconds
Answer: -Negative Reply-
Failure Reason: DNS query timed out
...
[Ingress]HSGW> dns-client query client-name HSGW-DNS query-type NAPTR
query-name APN2.apn.epc.mnc420.mcc300.3gppnetwork.org
Query Name: APN2.apn.epc.mnc420.mcc300.3gppnetwork.org
Query Type: NAPTR TTL: 60 seconds
Answer: -Negative Reply-
Failure Reason: Connection Refused
監控通訊協定（DNS選項）
監控協定報告所有DNS基礎設施資料包交換。監控使用者（稍後介紹）不會捕獲DNS資料包，即使發起了DNS交換的是使用者活動。
- 為了將請求與響應相匹配，查詢ID很有用。
但是：
- 在交換器到TCP的情況下，輸出不會指出此情況（輸出所示）。
- 輸出中的埠號不一定準確，例如埠= 0。
- 系統可能會將多個資料包（如APN查詢）組合成線路上的單個資料包，該資料包不會在此輸出級別上反映出來。這將繼續顯示每個APN的單獨資料包。
- 必須注意使用監控協定，以免系統過載。執行此操作前，請諮詢技術支援。
<<<<OUTBOUND 00:58:57:284 Eventid:5957(3)
DNS PDU Tx
from : 2001:5555:200:1011:304:281:: : 52816
to : 2001:5555:202:fffe:a0:e:0:3 : 0
bytes : 73
Query ID : 17034
Type : Query
Question : NAPTR ? APN2.apn.epc.mnc420.mcc300.3gppnetwork.org.
Additional :
Name : .
Ext-RCODE : 0
Type : OPT
UDPsize : 4096
INBOUND>>>>> 00:58:57:469 Eventid:5956(3)
DNS PDU Rx
from : 2001:5555:202:fffe:a0:e:0:3 : 0
to : 2001:5555:200:1011:304:281:: : 0
bytes : 16738
Query ID : 17034
Type : Response
Authoritative Answer : Yes
Response code : Success
Question : NAPTR ? APN2.apn.epc.mnc420.mcc300.3gppnetwork.org.
Answer :
Name : APN2.apn.epc.mnc420.mcc300.3gppnetwork.org.
TTL : 1800
Type : NAPTR
Order : 100
Preference : 50000
Flags : a
Service : x-3gpp-pgw:x-s2a-pmip
Regexp :
Replacement : topon.lb2.pgw01.PHLA.sa001.we.node.epc.mnc420.
mcc300.3gppnetwork.org.
Name : APN2.apn.epc.mnc420.mcc300.3gppnetwork.org.
TTL : 1800
Type : NAPTR
Order : 100
Preference : 50000
Flags : a
Service : x-3gpp-pgw:x-s5-gtp
Regexp :
Replacement : topon.lb1.pgw01.PHLA.sa001.we.node.epc.
mnc420.mcc300.3gppnetwork.org
此範例顯示三個APN，它們最終封裝到一個封包中，交換到TCP，每個APN超時兩秒，最後重試到同樣發生故障的輔助伺服器。
主伺服器: 2001:555:202:fffe:a0:e:0:3
輔助服務器：2001:555:203:fffe:c0:e:0:3
<<<<OUTBOUND 13:03:08:056 Eventid:5957(3)
DNS PDU Tx
from : 2001:5555:200:1011:106:281:: : 35428
to : 2001:5555:202:fffe:a0:e:0:3 : 53
bytes : 78
Query ID : 23363
Type : Query
Opcode : Standard Query
Message Truncated : No
Recursion Desired : Yes
Authentication reqd. : No
Question count : 1
Additional count : 1
Question : NAPTR ? APN1.apn.epc.mnc420.mcc300.3gppnetwork.org.
Additional :
Name : .
Ext-RCODE : 0
EDNS Version : 0
Class : 4096
Data Length : 0
Type : OPT
UDPsize : 4096
Monday October 13 2014
<<<<OUTBOUND 13:03:08:057 Eventid:5957(3)
DNS PDU Tx
from : 2001:5555:200:1011:106:281:: : 60489
to : 2001:5555:202:fffe:a0:e:0:3 : 53
bytes : 73
Query ID : 48443
Type : Query
Opcode : Standard Query
Message Truncated : No
Recursion Desired : Yes
Authentication reqd. : No
Question count : 1
Additional count : 1
Question : NAPTR ? APN3.apn.epc.mnc420.mcc300.3gppnetwork.org.
Additional :
Name : .
Ext-RCODE : 0
EDNS Version : 0
Class : 4096
Data Length : 0
Type : OPT
UDPsize : 4096
Monday October 13 2014
<<<<OUTBOUND 13:03:08:057 Eventid:5957(3)
DNS PDU Tx
from : 2001:5555:200:1011:106:281:: : 34309
to : 2001:5555:202:fffe:a0:e:0:3 : 53
bytes : 73
Query ID : 51787
Type : Query
Opcode : Standard Query
Message Truncated : No
Recursion Desired : Yes
Authentication reqd. : No
Question count : 1
Additional count : 1
Question : NAPTR ? APN2.apn.epc.mnc420.mcc300.3gppnetwork.org.
Additional :
Name : .
Ext-RCODE : 0
EDNS Version : 0
Class : 4096
Data Length : 0
Type : OPT
UDPsize : 4096
Monday October 13 2014
INBOUND>>>> 13:03:08:064 Eventid:5956(3)
DNS PDU Rx
from : 2001:5555:202:fffe:a0:e:0:3 : 53
to : 2001:5555:200:1011:106:281:: : 35428
bytes : 78
Query ID : 23363
Type : Response
Opcode : Standard Query
Message Truncated : Yes
Recursion Desired : Yes
Recursion Available : Yes
Authenticated Answer : No
Authoritative Answer : Yes
Response code : Success
Question count : 1
Answer count : 0
Authoritative count : 0
Additional count : 1
Question : NAPTR ? APN1.apn.epc.mnc420.mcc300.3gppnetwork.org.
Additional :
Name : .
Ext-RCODE : 0
EDNS Version : 0
Class : 4096
Data Length : 0
Type : OPT
UDPsize : 4096
Monday October 13 2014
INBOUND>>>> 13:03:08:064 Eventid:5956(3)
DNS PDU Rx
from : 2001:5555:202:fffe:a0:e:0:3 : 53
to : 2001:5555:200:1011:106:281:: : 60489
bytes : 73
Query ID : 48443
Type : Response
Opcode : Standard Query
Message Truncated : Yes
Recursion Desired : Yes
Recursion Available : Yes
Authenticated Answer : No
Authoritative Answer : Yes
Response code : Success
Question count : 1
Answer count : 0
Authoritative count : 0
Additional count : 1
Question : NAPTR ? APN3.apn.epc.mnc420.mcc300.3gppnetwork.org.
Additional :
Name : .
Ext-RCODE : 0
EDNS Version : 0
Class : 4096
Data Length : 0
Type : OPT
UDPsize : 4096
Monday October 13 2014
INBOUND>>>> 13:03:08:069 Eventid:5956(3)
DNS PDU Rx
from : 2001:5555:202:fffe:a0:e:0:3 : 53
to : 2001:5555:200:1011:106:281:: : 34309
bytes : 73
Query ID : 51787
Type : Response
Opcode : Standard Query
Message Truncated : Yes
Recursion Desired : Yes
Recursion Available : Yes
Authenticated Answer : No
Authoritative Answer : Yes
Response code : Success
Question count : 1
Answer count : 0
Authoritative count : 0
Additional count : 1
Question : NAPTR ? APN2.apn.epc.mnc420.mcc300.3gppnetwork.org.
Additional :
Name : .
Ext-RCODE : 0
EDNS Version : 0
Class : 4096
Data Length : 0
Type : OPT
UDPsize : 4096
Monday October 13 2014
<<<<OUTBOUND 13:03:08:147 Eventid:5957(3)
DNS PDU Tx
from : 2001:5555:200:1011:106:281:: : 36524
to : 2001:5555:202:fffe:a0:e:0:3 : 0
bytes : 78
Query ID : 23363
Type : Query
Opcode : Standard Query
Message Truncated : No
Recursion Desired : Yes
Authentication reqd. : No
Question count : 1
Additional count : 1
Question : NAPTR ? APN1.apn.epc.mnc420.mcc300.3gppnetwork.org.
Additional :
Name : .
Ext-RCODE : 0
EDNS Version : 0
Class : 4096
Data Length : 0
Type : OPT
UDPsize : 4096
Monday October 13 2014
<<<<OUTBOUND 13:03:08:147 Eventid:5957(3)
DNS PDU Tx
from : 2001:5555:200:1011:106:281:: : 36524
to : 2001:5555:202:fffe:a0:e:0:3 : 0
bytes : 73
Query ID : 48443
Type : Query
Opcode : Standard Query
Message Truncated : No
Recursion Desired : Yes
Authentication reqd. : No
Question count : 1
Additional count : 1
Question : NAPTR ? APN3.apn.epc.mnc420.mcc300.3gppnetwork.org.
Additional :
Name : .
Ext-RCODE : 0
EDNS Version : 0
Class : 4096
Data Length : 0
Type : OPT
UDPsize : 4096
Monday October 13 2014
<<<<OUTBOUND 13:03:08:147 Eventid:5957(3)
DNS PDU Tx
from : 2001:5555:200:1011:106:281:: : 36524
to : 2001:5555:202:fffe:a0:e:0:3 : 0
bytes : 73
Query ID : 51787
Type : Query
Opcode : Standard Query
Message Truncated : No
Recursion Desired : Yes
Authentication reqd. : No
Question count : 1
Additional count : 1
Question : NAPTR ? APN2.apn.epc.mnc420.mcc300.3gppnetwork.org.
Additional :
Name : .
Ext-RCODE : 0
EDNS Version : 0
Class : 4096
Data Length : 0
Type : OPT
UDPsize : 4096
Monday October 13 2014
<<<<OUTBOUND 13:03:10:157 Eventid:5957(3)
DNS PDU Tx
from : 2001:5555:200:1011:106:281:: : 57041
to : 2001:5555:203:fffe:c0:e:0:3 : 0
bytes : 78
Query ID : 23363
Type : Query
Opcode : Standard Query
Message Truncated : No
Recursion Desired : Yes
Authentication reqd. : No
Question count : 1
Additional count : 1
Question : NAPTR ? APN1.apn.epc.mnc420.mcc300.3gppnetwork.org.
Additional :
Name : .
Ext-RCODE : 0
EDNS Version : 0
Class : 4096
Data Length : 0
Type : OPT
UDPsize : 4096
Monday October 13 2014
<<<<OUTBOUND 13:03:10:157 Eventid:5957(3)
DNS PDU Tx
from : 2001:5555:200:1011:106:281:: : 57041
to : 2001:5555:203:fffe:c0:e:0:3 : 0
bytes : 73
Query ID : 48443
Type : Query
Opcode : Standard Query
Message Truncated : No
Recursion Desired : Yes
Authentication reqd. : No
Question count : 1
Additional count : 1
Question : NAPTR ? APN3.apn.epc.mnc420.mcc300.3gppnetwork.org.
Additional :
Name : .
Ext-RCODE : 0
EDNS Version : 0
Class : 4096
Data Length : 0
Type : OPT
UDPsize : 4096
Monday October 13 2014
<<<<OUTBOUND 13:03:10:157 Eventid:5957(3)
DNS PDU Tx
from : 2001:5555:200:1011:106:281:: : 57041
to : 2001:5555:203:fffe:c0:e:0:3 : 0
bytes : 73
Query ID : 51787
Type : Query
Opcode : Standard Query
Message Truncated : No
Recursion Desired : Yes
Authentication reqd. : No
Question count : 1
Additional count : 1
Question : NAPTR ? APN2.apn.epc.mnc420.mcc300.3gppnetwork.org.
Additional :
Name : .
Ext-RCODE : 0
EDNS Version : 0
Class : 4096
Data Length : 0
Type : OPT
UDPsize : 4096
此圖顯示三個APN封裝在一個資料包#10中。1 - 3中的原始UDP請求在4、5和7中響應，而TCP握手由資料包6、8和9組成。在這種情況下，伺服器在最初通過資料包11確認基於TCP的查詢後，立即在資料包12中重置連線。以下是可能需要疑難排解的問題的型別：
最後，來自同一捕獲，這是通過UDP成功查詢和響應NAPTR查詢，然後立即執行所需的AAAA查詢和響應，以解析NAPTR查詢返回的FQDN。此輸出與儲存為文本的Wireshark跟蹤相匹配：
Monday October 13 2014
<<<<OUTBOUND 13:03:11:535 Eventid:5957(3)
DNS PDU Tx
from : 2001:5555:200:1011:106:281:: : 38819
to : 2001:5555:202:fffe:a0:e:0:3 : 53
bytes : 87
Query ID : 55982
Type : Query
Opcode : Standard Query
Message Truncated : No
Recursion Desired : Yes
Authentication reqd. : No
Question count : 1
Additional count : 1
Question : NAPTR ? pgw02.PHLA.sa002.so.node.epc.mnc420.mcc300.3gppnetwork.org.
Additional :
Name : .
Ext-RCODE : 0
EDNS Version : 0
Class : 4096
Data Length : 0
Type : OPT
UDPsize : 4096
Monday October 13 2014
INBOUND>>>>> 13:03:11:543 Eventid:5956(3)
DNS PDU Rx
from : 2001:5555:202:fffe:a0:e:0:3 : 53
to : 2001:5555:200:1011:106:281:: : 38819
bytes : 307
Query ID : 55982
Type : Response
Opcode : Standard Query
Message Truncated : No
Recursion Desired : Yes
Recursion Available : Yes
Authenticated Answer : No
Authoritative Answer : Yes
Response code : Success
Question count : 1
Answer count : 2
Authoritative count : 0
Additional count : 1
Question : NAPTR ? pgw02.PHLA.sa002.so.node.epc.mnc420.
mcc300.3gppnetwork.org.
Answer :
Name : pgw02.PHLA.sa002.so.node.epc.mnc420.mcc300.3gppnetwork.org.
TTL : 1800
Class : IN
Data Length : 99
Type : NAPTR
Order : 100
Preference : 50000
Flags : a
Service : x-3gpp-pgw:x-s2a-pmip
Regexp :
Replacement : topon.lb2.pgw02.PHLA.sa002.so.node.epc.mnc420.
mcc300.3gppnetwork.org.
Name : pgw02.PHLA.sa002.so.node.epc.mnc420.mcc300.
3gppnetwork.org.
TTL : 1800
Class : IN
Data Length : 97
Type : NAPTR
Order : 100
Preference : 50000
Flags : a
Service : x-3gpp-pgw:x-s5-gtp
Regexp :
Replacement : topon.lb1.pgw02.PHLA.sa002.so.node.epc.mnc420.
mcc300.3gppnetwork.org.
Additional :
Name : .
Ext-RCODE : 0
EDNS Version : 0
Class : 4096
Data Length : 0
Type : OPT
UDPsize : 4096
Monday October 13 2014
<<<<OUTBOUND 13:03:11:543 Eventid:5957(3)
DNS PDU Tx
from : 2001:5555:200:1011:106:281:: : 50002
to : 2001:5555:202:fffe:a0:e:0:3 : 53
bytes : 97
Query ID : 1974
Type : Query
Opcode : Standard Query
Message Truncated : No
Recursion Desired : Yes
Authentication reqd. : No
Question count : 1
Additional count : 1
Question : AAAA? topon.lb2.pgw02.PHLA.sa002.so.node.epc.
mnc420.mcc300.3gppnetwork.org.
Additional :
Name : .
Ext-RCODE : 0
EDNS Version : 0
Class : 4096
Data Length : 0
Type : OPT
UDPsize : 4096
Monday October 13 2014
INBOUND>>>>> 13:03:11:551 Eventid:5956(3)
DNS PDU Rx
from : 2001:5555:202:fffe:a0:e:0:3 : 53
to : 2001:5555:200:1011:106:281:: : 50002
bytes : 125
Query ID : 1974
Type : Response
Opcode : Standard Query
Message Truncated : No
Recursion Desired : Yes
Recursion Available : Yes
Authenticated Answer : No
Authoritative Answer : Yes
Response code : Success
Question count : 1
Answer count : 1
Authoritative count : 0
Additional count : 1
Question : AAAA? topon.lb2.pgw02.PHLA.sa002.so.node.epc.
mnc420.mcc300.3gppnetwork.org.
Answer :
Name : topon.lb2.pgw02.PHLA.sa002.so.node.epc.mnc420.
mcc300.3gppnetwork.org.
TTL : 1800
Class : IN
Data Length : 16
Type : AAAA
Address : 2001:5555:200:1000:201:201::
Additional :
Name : .
Ext-RCODE : 0
EDNS Version : 0
Class : 4096
Data Length : 0
Type : OPT
UDPsize : 4096
Corresponding Wireshark trace:
Frame 25: 151 bytes on wire (1208 bits), 151 bytes captured (1208 bits)
Linux cooked capture
Internet Protocol Version 6, Src: HSGW, Dst: DNS_Server
User Datagram Protocol, Src Port: 38819 (38819), Dst Port: domain (53)
Domain Name System (query)
[Response In: 26]
Transaction ID: 0xdaae
Flags: 0x0100 Standard query
Questions: 1
Answer RRs: 0
Authority RRs: 0
Additional RRs: 1
Queries
pgw02.PHLA.sa002.so.node.epc.mnc420.mcc300.3gppnetwork.org: type NAPTR, class IN
Additional records
<Root>: type OPT
Name: <Root>
Type: OPT (EDNS0 option)
UDP payload size: 4096
Higher bits in extended RCODE: 0x0
EDNS0 version: 0
Z: 0x0
Data length: 0
Frame 26: 371 bytes on wire (2968 bits), 371 bytes captured (2968 bits)
Linux cooked capture
Internet Protocol Version 6, Src: DNS_Server, Dst: HSGW
User Datagram Protocol, Src Port: domain (53), Dst Port: 38819 (38819)
Domain Name System (response)
[Request In: 25]
[Time: 0.008125000 seconds]
Transaction ID: 0xdaae
Flags: 0x8580 Standard query response, No error
Questions: 1
Answer RRs: 2
Authority RRs: 0
Additional RRs: 1
Queries
pgw02.PHLA.sa002.so.node.epc.mnc420.mcc300.3gppnetwork.org: type NAPTR, class IN
Answers
pgw02.PHLA.sa002.so.node.epc.mnc420.mcc300.3gppnetwork.org:
type NAPTR, class IN, order 100, preference 50000, flags a
Name: pgw02.PHLA.sa002.so.node.epc.mnc420.mcc300.3gppnetwork.org
Type: NAPTR (Naming authority pointer)
Class: IN (0x0001)
Time to live: 30 minutes
Data length: 99
Order: 100
Preference: 50000
Flags length: 1
Flags: "a"
Service length: 21
Service: "x-3gpp-pgw:x-s2a-pmip"
Regex length: 0
Regex: ""
Replacement length: 70
Replacement: topon.lb2.pgw02.PHLA.sa002.so.node.epc.
mnc420.mcc300.3gppnetwork.org
pgw02.PHLA.sa002.so.node.epc.mnc420.mcc300.3gppnetwork.org:
type NAPTR, class IN, order 100, preference 50000, flags a
Name: pgw02.PHLA.sa002.so.node.epc.mnc420.mcc300.3gppnetwork.org
Type: NAPTR (Naming authority pointer)
Class: IN (0x0001)
Time to live: 30 minutes
Data length: 97
Order: 100
Preference: 50000
Flags length: 1
Flags: "a"
Service length: 19
Service: "x-3gpp-pgw:x-s5-gtp"
Regex length: 0
Regex: ""
Replacement length: 70
Replacement: topon.lb1.pgw02.PHLA.sa002.so.node.epc.
mnc420.mcc300.3gppnetwork.org
Additional records
<Root>: type OPT
Name: <Root>
Type: OPT (EDNS0 option)
UDP payload size: 4096
Higher bits in extended RCODE: 0x0
EDNS0 version: 0
Z: 0x0
Data length: 0
Frame 27: 161 bytes on wire (1288 bits), 161 bytes captured (1288 bits)
Linux cooked capture
Internet Protocol Version 6, Src: HSGW, Dst: DNS_Server
User Datagram Protocol, Src Port: 50002 (50002), Dst Port: domain (53)
Domain Name System (query)
[Response In: 28]
Transaction ID: 0x07b6
Flags: 0x0100 Standard query
Questions: 1
Answer RRs: 0
Authority RRs: 0
Additional RRs: 1
Queries
topon.lb2.pgw02.PHLA.sa002.so.node.epc.mnc420.mcc300.3gppnetwork.org:
type AAAA, class IN
Additional records
<Root>: type OPT
Name: <Root>
Type: OPT (EDNS0 option)
UDP payload size: 4096
Higher bits in extended RCODE: 0x0
EDNS0 version: 0
Z: 0x0
Data length: 0
Frame 28: 189 bytes on wire (1512 bits), 189 bytes captured (1512 bits)
Linux cooked capture
Internet Protocol Version 6, Src: DNS_Server , Dst: HSGW
User Datagram Protocol, Src Port: domain (53), Dst Port: 50002 (50002)
Domain Name System (response)
[Request In: 27]
[Time: 0.007622000 seconds]
Transaction ID: 0x07b6
Flags: 0x8580 Standard query response, No error
Questions: 1
Answer RRs: 1
Authority RRs: 0
Additional RRs: 1
Queries
topon.lb2.pgw02.PHLA.sa002.so.node.epc.mnc420.mcc300.3gppnetwork.org:
type AAAA, class IN
Answers
topon.lb2.pgw02.PHLA.sa002.so.node.epc.mnc420.mcc300.3gppnetwork.org:
type AAAA, class IN, addr 2001:5555:200:1000:201:201::
Name: topon.lb2.pgw02.PHLA.sa002.so.node.epc.mnc420.mcc300.3gppnetwork.org
Type: AAAA (IPv6 address)
Class: IN (0x0001)
Time to live: 30 minutes
Data length: 16
Addr: 2001:5555:200:1000:201:201::
Additional records
<Root>: type OPT
Name: <Root>
Type: OPT (EDNS0 option)
UDP payload size: 4096
Higher bits in extended RCODE: 0x0
EDNS0 version: 0
Z: 0x0
Data length: 0
記錄檔
12.2版新增了一項功能，即在兩分鐘時間內發生大量連線拒絕錯誤，導致中斷情況下重新繫結為DNS使用者端設定的IP位址。示例日誌條目為：
[vpn 5795 error] [1/0/30805 <vpnmgr:4> vpnmgr_msg.c:13773]
[context: Ingress, contextID: 4] [software internal system syslog]
Ingress: Rebinding DNS-CLIENT as connection refused errors
(<# of failures>) occuring continously
範例：
Jun 2 00:03:36 [10.142.250.226.171.216] evlogd: [local-60sec36.031]
[vpn 5450 error] [1/0/30805 <vpnmgr:4> vpnmgr_msg.c:13680] [context: Ingress,
contextID: 4] [software internal system syslog] Connection
refused for DNS query on QNAME:APN1.apn.epc.mnc420.mcc300.3gppnetwork.org
and QTYPE:NAPTR....... Many more of these logs
Jun 2 00:05:35 [10.142.250.226.171.216] evlogd: [local-60sec35.058]
[vpn 5450 error] [1/0/30805 <vpnmgr:4> vpnmgr_msg.c:13680]
[context: Ingress, contextID: 4] [software internal system syslog]
Connection refused for DNS query on QNAME:APN1.apn.epc.mnc420.mcc300.3gppnetwork.org
and QTYPE:NAPTR
Jun 2 00:05:35 [10.142.250.226.171.216] evlogd: [local-60sec35.058]
[vpn 5795 error] [1/0/30805 <vpnmgr:4> vpnmgr_msg.c:13773]
[context: Ingress, contextID: 4] [software internal system syslog]
Ingress: Rebinding DNS-CLIENT as connection refused errors (3132) occuring continously
封包捕獲
發現了一些棘手的DNS問題，需要捕獲資料包以確定從DNS伺服器傳送和接收回的內容。統計資料和監控協定可能沒有提供足夠的資訊。
- 技術支援能夠使用TCP轉儲工具捕獲DNS資料包，並可能建議將此方法作為故障排除過程的一部分。
- 根據任何介入的防火牆和可以協商TCP/IP連線的防火牆，捕獲點非常重要。可能需要多個捕獲點才能找到問題的根本原因。
- 使用Wireshark中的Follow TCP stream選單選項過濾特定的TCP連線，以便更輕鬆地導航大型檔案中的多個TCP流。
排除DNS與呼叫控制相關的故障
如前所述，DNS本身不工作，但它是呼叫控制流的啟用程式或元件。例如，在eHRPD的情況下，需要確定PGW要連線到時，呼叫點需要DNS。如果在流的此點發生故障，則相應的呼叫控制統計資訊將反映這一點。
show hsgw-service statistics
如果DNS發生故障，預計「No PGW Available」（無PGW可用）計數器會增加。由於在嘗試向PGW發出請求之前呼叫將失敗，因此「show mag statistics」不會捕獲此事件（這些事件不會統計傳送的繫結更新）
範例：
[Ingress]HSGW> show hsgw statistics all
Monday June 02 00:49:06 UTC 2014
Total PDNs Rejected Reason:
No PGW Available: 9549866
[Ingress]HSGW> show hsgw statistics all
Monday June 02 00:49:16 UTC 2014
No PGW Available: 9554113
監控訂戶
請注意，在監控訂閱伺服器中不會捕獲DNS資料包本身。儘管它們確實由單個使用者活動觸發，但它們的工作獨立於給定使用者，並且必須如前所述由監控協定捕獲。
出現DNS基礎設施控制消息，例如「No LMA address available for APN <APN Name> in subscriber profile， PDN connection failed」，並使用「Error-Code(6)=No-PDN-GW-Available(3)」將VSNCP Conf-Rej傳送到訂戶。
範例：
INBOUND>>>> 00:25:26:925 Eventid:25000(0) PPP Rx PDU (72) VSNCP 72:
Conf-Req(2), OUI=cf0002(3GPP2) , PDN-ID(1)=00, PDN-APN-Name(2)=\013APN1,
PDN-Type(3)=IPv4,IPv6(3), PDN-Address(4)=(Null), PCO(5)
{Protocol(0) = PPP(0),{IPCP
(1): Conf-Req(1), Pri-DNS=0.0.0.0, Sec-DNS=0.0.0.0},IPv6-DNS-Address(2)=Req,IP-Address-
Allocation-via-NAS-Signaling(3),}, Attach-Type(7)=Initial(1),
IPv4-Default-Router-Address(8)=0.0.0.0, Address-Allocation-Cause(9)=Null(0)
***CONTROL*** 00:25:27:054 Eventid:11813
No LMA address available for APNin subscriber profile, PDN connection failed
Monday June 02 2014
<<<<OUTBOUND 00:25:27:054 Eventid:25001(0)
PPP Tx PDU (14)
VSNCP 14: Conf-Req(1), OUI=cf0002(3GPP2) , PDN-ID(1)=00
Monday June 02 2014
<<<<OUTBOUND 00:25:27:054 Eventid:25001(0)
PPP Tx PDU (52)
VSNCP 52: Conf-Rej(2), OUI=cf0002(3GPP2) , PDN-ID(1)=00, PDN-APN-Name(2)=\013APN1,
PDN-Type(3)=IPv4,IPv6(3), PDN-Address(4)=(Null), PCO(5){Protocol(0)
= PPP(0),}, Attach-Type(7)=Initial(1), IPv4-Default-Router-Address(8)=0.0.0.0,
Address-Allocation-Cause(9)=Null(0), Error-Code(6)=No-PDN-GW-Available(3)
記錄檔
查詢與呼叫控制相關的任何錯誤日誌。
範例：
Jun 2 00:25:27 [10.142.250.226.171.216] evlogd: [local-60sec27.054]
[sessmgr 11813 error] [15/0/5827 <sessmgr:71> sessmgr_mag.c:3595]
[callid 14ec7ad1] [context: Ingress, contextID: 4] [software internal
system protocol-log syslog] No LMA address available for APNin
subscriber profile, PDN connection failed
相關資訊
修訂記錄
| 修訂 | 發佈日期 | 意見 |
|---|---|---|
1.0 |
21-Apr-2016 |
初始版本 |
意見