วิธีการตรวจสอบการตั้งค่าแบบสุ่มบนพอร์ตไคลเอนต์ TCP ที่เชื่อมต่อผ่านทางวนกลับไปยังเซิร์ฟเวอร์

ฉันมีชุดทดสอบที่เริ่มต้นเซิร์ฟเวอร์บน localhost แล้วรันการทดสอบหลายพันครั้งซึ่งรวมถึงการเริ่มต้นและหยุดไคลเอ็นต์ที่เชื่อมต่อกับเซิร์ฟเวอร์ในเครื่องนี้ในเครื่องเดียวกัน ฉันพยายามค้นหาสาเหตุของ RST ที่ลูกค้าส่งไปยังเซิร์ฟเวอร์

นี่คือลำดับเหตุการณ์:

ไคลเอ็นต์เริ่มต้น SYN
เซิร์ฟเวอร์ส่งกลับ SYN, ACK
ไคลเอนต์ส่ง RST (แทน ACK และสร้างการเชื่อมต่อ)

การสังเกตการณ์หนึ่งครั้งในหลาย ๆ ครั้งเซิร์ฟเวอร์ใช้ CPU ประมาณ 99 เปอร์เซ็นต์แม้ว่ามันจะกลับมาเป็นปกติในไม่กี่วินาที / นาที

ตอนแรกฉันคิดว่าอาจเป็นเพราะลูกค้าใช้พอร์ตจากการเชื่อมต่อที่ปิดก่อนหน้านี้ซึ่งอยู่ในสถานะ TIME_WAIT และเมื่อเซิร์ฟเวอร์ส่ง SYN, ACK ในไคลเอ็นต์การเชื่อมต่อนั้นออก RST แม้ว่าฉันจะสงสัยว่าทำไมลูกค้าควรใช้พอร์ตในสถานะ TIME_WAIT แต่ฉันใช้ fedora core 4 แบบเก่าและคิดว่าอาจจะไม่ได้ใช้ TCP / IP :-)

ตอนนี้ฉันไม่เชื่อว่าเป็นเหตุผลเพราะการปรับแต่งทั้งหมดที่ทำในการแก้ไขปัญหาข้างต้นไม่ได้ช่วยบรรเทาปัญหา FYI ต่อไปนี้เป็นการเปลี่ยนแปลงที่ฉันได้ลอง/etc/sysctl.conf:

net.ipv4.ip_local_port_range = 1024     65535
net.ipv4.tcp_fin_timeout = 15
net.ipv4.tcp_rfc1337 = 1
net.ipv4.tcp_tw_reuse = 1

อีกประเด็นหนึ่งปัญหานี้ไม่สอดคล้องกัน ในความเป็นจริงฉันสามารถทำซ้ำปัญหานี้หลังจากผ่านไป 15 ถึง 35 รอบของการรีสตาร์ทเซิร์ฟเวอร์และทำการทดสอบไคลเอ็นต์ทั้งหมด

ฉันหมดเหตุผลทั้งหมดที่ฉันสามารถคิดได้ว่าเหตุใดจึงเกิดเหตุการณ์เช่นนี้ขึ้นดังนั้นให้ฉันรู้ว่ามีใครมีความคิดเกี่ยวกับสิ่งที่อาจเกิดขึ้น

รายละเอียดแพ็คเก็ต

Date & Time                No.     Time        Source                Destination           Protocol Length Source port Dest port Info
2014-06-25 14:49:45.378209 1032719 1858.494749 ::1                   ::1                   TCP      94     netview-aix-5 navisphere netview-aix-5 > navisphere [SYN] Seq=0 Win=32752 Len=0 MSS=16376 SACK_PERM=1 TSval=1587252 TSecr=0 WS=128

Frame 1032719: 94 bytes on wire (752 bits), 94 bytes captured (752 bits)
    Arrival Time: Jun 25, 2014 14:49:45.378209000 EDT
    Epoch Time: 1403722185.378209000 seconds
    [Time delta from previous captured frame: 0.005893000 seconds]
    [Time delta from previous displayed frame: 0.000000000 seconds]
    [Time since reference or first frame: 1858.494749000 seconds]
    Frame Number: 1032719
    Frame Length: 94 bytes (752 bits)
    Capture Length: 94 bytes (752 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ipv6:tcp]
    [Coloring Rule Name: TCP SYN/FIN]
    [Coloring Rule String: tcp.flags & 0x02 || tcp.flags.fin == 1]
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Destination: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Source: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Type: IPv6 (0x86dd)
Internet Protocol Version 6, Src: ::1 (::1), Dst: ::1 (::1)
    0110 .... = Version: 6
        [0110 .... = This field makes the filter "ip.version == 6" possible: 6]
    .... 0000 0000 .... .... .... .... .... = Traffic class: 0x00000000
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Field: Default (0x00000000)
        .... .... ..0. .... .... .... .... .... = ECN-Capable Transport (ECT): Not set
        .... .... ...0 .... .... .... .... .... = ECN-CE: Not set
    .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000
    Payload length: 40
    Next header: TCP (0x06)
    Hop limit: 64
    Source: ::1 (::1)
    Destination: ::1 (::1)
Transmission Control Protocol, Src Port: netview-aix-5 (1665), Dst Port: navisphere (2162), Seq: 0, Len: 0
    Source port: netview-aix-5 (1665)
    Destination port: navisphere (2162)
    [Stream index: 3374]
    Sequence number: 0    (relative sequence number)
    Header length: 40 bytes
    Flags: 0x02 (SYN)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...0 .... = Acknowledgement: Not set
        .... .... 0... = Push: Not set
        .... .... .0.. = Reset: Not set
        .... .... ..1. = Syn: Set
            [Expert Info (Chat/Sequence): Connection establish request (SYN): server port navisphere]
        .... .... ...0 = Fin: Not set
    Window size value: 32752
    [Calculated window size: 32752]
    Checksum: 0xf489 [validation disabled]
        [Good Checksum: False]
        [Bad Checksum: False]
    Options: (20 bytes)
        Maximum segment size: 16376 bytes
        TCP SACK Permitted Option: True
        Timestamps: TSval 1587252, TSecr 0
        No-Operation (NOP)
        Window scale: 7 (multiply by 128)

Date & Time                No.     Time        Source                Destination           Protocol Length Source port Dest port Info
2014-06-25 14:49:45.378222 1032720 1858.494762 ::1                   ::1                   TCP      94     navisphere  netview-aix-5 navisphere > netview-aix-5 [SYN, ACK] Seq=0 Ack=1 Win=32728 Len=0 MSS=16376 SACK_PERM=1 TSval=1587252 TSecr=1587252 WS=128

Frame 1032720: 94 bytes on wire (752 bits), 94 bytes captured (752 bits)
    Arrival Time: Jun 25, 2014 14:49:45.378222000 EDT
    Epoch Time: 1403722185.378222000 seconds
    [Time delta from previous captured frame: 0.000013000 seconds]
    [Time delta from previous displayed frame: 0.000013000 seconds]
    [Time since reference or first frame: 1858.494762000 seconds]
    Frame Number: 1032720
    Frame Length: 94 bytes (752 bits)
    Capture Length: 94 bytes (752 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ipv6:tcp]
    [Coloring Rule Name: TCP SYN/FIN]
    [Coloring Rule String: tcp.flags & 0x02 || tcp.flags.fin == 1]
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Destination: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Source: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Type: IPv6 (0x86dd)
Internet Protocol Version 6, Src: ::1 (::1), Dst: ::1 (::1)
    0110 .... = Version: 6
        [0110 .... = This field makes the filter "ip.version == 6" possible: 6]
    .... 0000 0000 .... .... .... .... .... = Traffic class: 0x00000000
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Field: Default (0x00000000)
        .... .... ..0. .... .... .... .... .... = ECN-Capable Transport (ECT): Not set
        .... .... ...0 .... .... .... .... .... = ECN-CE: Not set
    .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000
    Payload length: 40
    Next header: TCP (0x06)
    Hop limit: 64
    Source: ::1 (::1)
    Destination: ::1 (::1)
Transmission Control Protocol, Src Port: navisphere (2162), Dst Port: netview-aix-5 (1665), Seq: 0, Ack: 1, Len: 0
    Source port: navisphere (2162)
    Destination port: netview-aix-5 (1665)
    [Stream index: 3374]
    Sequence number: 0    (relative sequence number)
    Acknowledgement number: 1    (relative ack number)
    Header length: 40 bytes
    Flags: 0x12 (SYN, ACK)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...1 .... = Acknowledgement: Set
        .... .... 0... = Push: Not set
        .... .... .0.. = Reset: Not set
        .... .... ..1. = Syn: Set
            [Expert Info (Chat/Sequence): Connection establish acknowledge (SYN+ACK): server port navisphere]
        .... .... ...0 = Fin: Not set
    Window size value: 32728
    [Calculated window size: 32728]
    Checksum: 0xf7fa [validation disabled]
        [Good Checksum: False]
        [Bad Checksum: False]
    Options: (20 bytes)
        Maximum segment size: 16376 bytes
        TCP SACK Permitted Option: True
        Timestamps: TSval 1587252, TSecr 1587252
        No-Operation (NOP)
        Window scale: 7 (multiply by 128)
    [SEQ/ACK analysis]
        [This is an ACK to the segment in frame: 1032719]
        [The RTT to ACK the segment was: 0.000013000 seconds]

Date & Time                No.     Time        Source                Destination           Protocol Length Source port Dest port Info
2014-06-25 14:49:45.378228 1032721 1858.494768 ::1                   ::1                   TCP      74     netview-aix-5 navisphere netview-aix-5 > navisphere [RST] Seq=1 Win=0 Len=0

Frame 1032721: 74 bytes on wire (592 bits), 74 bytes captured (592 bits)
    Arrival Time: Jun 25, 2014 14:49:45.378228000 EDT
    Epoch Time: 1403722185.378228000 seconds
    [Time delta from previous captured frame: 0.000006000 seconds]
    [Time delta from previous displayed frame: 0.000006000 seconds]
    [Time since reference or first frame: 1858.494768000 seconds]
    Frame Number: 1032721
    Frame Length: 74 bytes (592 bits)
    Capture Length: 74 bytes (592 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ipv6:tcp]
    [Coloring Rule Name: TCP RST]
    [Coloring Rule String: tcp.flags.reset eq 1]
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Destination: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Source: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Type: IPv6 (0x86dd)
Internet Protocol Version 6, Src: ::1 (::1), Dst: ::1 (::1)
    0110 .... = Version: 6
        [0110 .... = This field makes the filter "ip.version == 6" possible: 6]
    .... 0000 0000 .... .... .... .... .... = Traffic class: 0x00000000
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Field: Default (0x00000000)
        .... .... ..0. .... .... .... .... .... = ECN-Capable Transport (ECT): Not set
        .... .... ...0 .... .... .... .... .... = ECN-CE: Not set
    .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000
    Payload length: 20
    Next header: TCP (0x06)
    Hop limit: 64
    Source: ::1 (::1)
    Destination: ::1 (::1)
Transmission Control Protocol, Src Port: netview-aix-5 (1665), Dst Port: navisphere (2162), Seq: 1, Len: 0
    Source port: netview-aix-5 (1665)
    Destination port: navisphere (2162)
    [Stream index: 3374]
    Sequence number: 1    (relative sequence number)
    Header length: 20 bytes
    Flags: 0x04 (RST)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...0 .... = Acknowledgement: Not set
        .... .... 0... = Push: Not set
        .... .... .1.. = Reset: Set
            [Expert Info (Chat/Sequence): Connection reset (RST)]
        .... .... ..0. = Syn: Not set
        .... .... ...0 = Fin: Not set
    Window size value: 0
    [Calculated window size: 0]
    [Window size scaling factor: 128]
    Checksum: 0x4eea [validation disabled]
        [Good Checksum: False]
        [Bad Checksum: False]

Date & Time                No.     Time        Source                Destination           Protocol Length Source port Dest port Info
2014-06-25 14:49:48.375927 1032722 1861.492467 ::1                   ::1                   TCP      94     netview-aix-5 navisphere netview-aix-5 > navisphere [SYN] Seq=0 Win=32752 Len=0 MSS=16376 SACK_PERM=1 TSval=1588002 TSecr=0 WS=128

Frame 1032722: 94 bytes on wire (752 bits), 94 bytes captured (752 bits)
    Arrival Time: Jun 25, 2014 14:49:48.375927000 EDT
    Epoch Time: 1403722188.375927000 seconds
    [Time delta from previous captured frame: 2.997699000 seconds]
    [Time delta from previous displayed frame: 2.997699000 seconds]
    [Time since reference or first frame: 1861.492467000 seconds]
    Frame Number: 1032722
    Frame Length: 94 bytes (752 bits)
    Capture Length: 94 bytes (752 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ipv6:tcp]
    [Coloring Rule Name: TCP SYN/FIN]
    [Coloring Rule String: tcp.flags & 0x02 || tcp.flags.fin == 1]
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Destination: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Source: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Type: IPv6 (0x86dd)
Internet Protocol Version 6, Src: ::1 (::1), Dst: ::1 (::1)
    0110 .... = Version: 6
        [0110 .... = This field makes the filter "ip.version == 6" possible: 6]
    .... 0000 0000 .... .... .... .... .... = Traffic class: 0x00000000
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Field: Default (0x00000000)
        .... .... ..0. .... .... .... .... .... = ECN-Capable Transport (ECT): Not set
        .... .... ...0 .... .... .... .... .... = ECN-CE: Not set
    .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000
    Payload length: 40
    Next header: TCP (0x06)
    Hop limit: 64
    Source: ::1 (::1)
    Destination: ::1 (::1)
Transmission Control Protocol, Src Port: netview-aix-5 (1665), Dst Port: navisphere (2162), Seq: 0, Len: 0
    Source port: netview-aix-5 (1665)
    Destination port: navisphere (2162)
    [Stream index: 3374]
    Sequence number: 0    (relative sequence number)
    Header length: 40 bytes
    Flags: 0x02 (SYN)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...0 .... = Acknowledgement: Not set
        .... .... 0... = Push: Not set
        .... .... .0.. = Reset: Not set
        .... .... ..1. = Syn: Set
            [Expert Info (Chat/Sequence): Connection establish request (SYN): server port navisphere]
        .... .... ...0 = Fin: Not set
    Window size value: 32752
    [Calculated window size: 32752]
    Checksum: 0xf19b [validation disabled]
        [Good Checksum: False]
        [Bad Checksum: False]
    Options: (20 bytes)
        Maximum segment size: 16376 bytes
        TCP SACK Permitted Option: True
        Timestamps: TSval 1588002, TSecr 0
        No-Operation (NOP)
        Window scale: 7 (multiply by 128)

Date & Time                No.     Time        Source                Destination           Protocol Length Source port Dest port Info
2014-06-25 14:49:48.375950 1032723 1861.492490 ::1                   ::1                   TCP      94     navisphere  netview-aix-5 [TCP Previous segment lost] navisphere > netview-aix-5 [SYN, ACK] Seq=2997725 Ack=1 Win=32728 Len=0 MSS=16376 SACK_PERM=1 TSval=1588002 TSecr=1588002 WS=128

Frame 1032723: 94 bytes on wire (752 bits), 94 bytes captured (752 bits)
    Arrival Time: Jun 25, 2014 14:49:48.375950000 EDT
    Epoch Time: 1403722188.375950000 seconds
    [Time delta from previous captured frame: 0.000023000 seconds]
    [Time delta from previous displayed frame: 0.000023000 seconds]
    [Time since reference or first frame: 1861.492490000 seconds]
    Frame Number: 1032723
    Frame Length: 94 bytes (752 bits)
    Capture Length: 94 bytes (752 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ipv6:tcp]
    [Coloring Rule Name: Bad TCP]
    [Coloring Rule String: tcp.analysis.flags]
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Destination: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Source: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Type: IPv6 (0x86dd)
Internet Protocol Version 6, Src: ::1 (::1), Dst: ::1 (::1)
    0110 .... = Version: 6
        [0110 .... = This field makes the filter "ip.version == 6" possible: 6]
    .... 0000 0000 .... .... .... .... .... = Traffic class: 0x00000000
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Field: Default (0x00000000)
        .... .... ..0. .... .... .... .... .... = ECN-Capable Transport (ECT): Not set
        .... .... ...0 .... .... .... .... .... = ECN-CE: Not set
    .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000
    Payload length: 40
    Next header: TCP (0x06)
    Hop limit: 64
    Source: ::1 (::1)
    Destination: ::1 (::1)
Transmission Control Protocol, Src Port: navisphere (2162), Dst Port: netview-aix-5 (1665), Seq: 2997725, Ack: 1, Len: 0
    Source port: navisphere (2162)
    Destination port: netview-aix-5 (1665)
    [Stream index: 3374]
    Sequence number: 2997725    (relative sequence number)
    Acknowledgement number: 1    (relative ack number)
    Header length: 40 bytes
    Flags: 0x12 (SYN, ACK)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...1 .... = Acknowledgement: Set
        .... .... 0... = Push: Not set
        .... .... .0.. = Reset: Not set
        .... .... ..1. = Syn: Set
            [Expert Info (Chat/Sequence): Connection establish acknowledge (SYN+ACK): server port navisphere]
        .... .... ...0 = Fin: Not set
    Window size value: 32728
    [Calculated window size: 32728]
    Checksum: 0x3414 [validation disabled]
        [Good Checksum: False]
        [Bad Checksum: False]
    Options: (20 bytes)
        Maximum segment size: 16376 bytes
        TCP SACK Permitted Option: True
        Timestamps: TSval 1588002, TSecr 1588002
        No-Operation (NOP)
        Window scale: 7 (multiply by 128)
    [SEQ/ACK analysis]
        [This is an ACK to the segment in frame: 1032722]
        [The RTT to ACK the segment was: 0.000023000 seconds]
        [TCP Analysis Flags]
            [A segment before this frame was lost]
                [Expert Info (Warn/Sequence): Previous segment lost (common at capture start)]

Date & Time                No.     Time        Source                Destination           Protocol Length Source port Dest port Info
2014-06-25 14:49:48.375958 1032724 1861.492498 ::1                   ::1                   TCP      74     netview-aix-5 navisphere netview-aix-5 > navisphere [RST] Seq=1 Win=0 Len=0

Frame 1032724: 74 bytes on wire (592 bits), 74 bytes captured (592 bits)
    Arrival Time: Jun 25, 2014 14:49:48.375958000 EDT
    Epoch Time: 1403722188.375958000 seconds
    [Time delta from previous captured frame: 0.000008000 seconds]
    [Time delta from previous displayed frame: 0.000008000 seconds]
    [Time since reference or first frame: 1861.492498000 seconds]
    Frame Number: 1032724
    Frame Length: 74 bytes (592 bits)
    Capture Length: 74 bytes (592 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ipv6:tcp]
    [Coloring Rule Name: TCP RST]
    [Coloring Rule String: tcp.flags.reset eq 1]
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Destination: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Source: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Type: IPv6 (0x86dd)
Internet Protocol Version 6, Src: ::1 (::1), Dst: ::1 (::1)
    0110 .... = Version: 6
        [0110 .... = This field makes the filter "ip.version == 6" possible: 6]
    .... 0000 0000 .... .... .... .... .... = Traffic class: 0x00000000
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Field: Default (0x00000000)
        .... .... ..0. .... .... .... .... .... = ECN-Capable Transport (ECT): Not set
        .... .... ...0 .... .... .... .... .... = ECN-CE: Not set
    .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000
    Payload length: 20
    Next header: TCP (0x06)
    Hop limit: 64
    Source: ::1 (::1)
    Destination: ::1 (::1)
Transmission Control Protocol, Src Port: netview-aix-5 (1665), Dst Port: navisphere (2162), Seq: 1, Len: 0
    Source port: netview-aix-5 (1665)
    Destination port: navisphere (2162)
    [Stream index: 3374]
    Sequence number: 1    (relative sequence number)
    Header length: 20 bytes
    Flags: 0x04 (RST)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...0 .... = Acknowledgement: Not set
        .... .... 0... = Push: Not set
        .... .... .1.. = Reset: Set
            [Expert Info (Chat/Sequence): Connection reset (RST)]
        .... .... ..0. = Syn: Not set
        .... .... ...0 = Fin: Not set
    Window size value: 0
    [Calculated window size: 0]
    [Window size scaling factor: 128]
    Checksum: 0x4eea [validation disabled]
        [Good Checksum: False]
        [Bad Checksum: False]

Date & Time                No.     Time        Source                Destination           Protocol Length Source port Dest port Info
2014-06-25 14:49:54.376072 1032725 1867.492612 ::1                   ::1                   TCP      94     netview-aix-5 navisphere netview-aix-5 > navisphere [SYN] Seq=0 Win=32752 Len=0 MSS=16376 SACK_PERM=1 TSval=1589502 TSecr=0 WS=128

Frame 1032725: 94 bytes on wire (752 bits), 94 bytes captured (752 bits)
    Arrival Time: Jun 25, 2014 14:49:54.376072000 EDT
    Epoch Time: 1403722194.376072000 seconds
    [Time delta from previous captured frame: 6.000114000 seconds]
    [Time delta from previous displayed frame: 6.000114000 seconds]
    [Time since reference or first frame: 1867.492612000 seconds]
    Frame Number: 1032725
    Frame Length: 94 bytes (752 bits)
    Capture Length: 94 bytes (752 bits)
    [Frame is marked: False]
    [Frame is ignored: False]
    [Protocols in frame: eth:ipv6:tcp]
    [Coloring Rule Name: TCP SYN/FIN]
    [Coloring Rule String: tcp.flags & 0x02 || tcp.flags.fin == 1]
Ethernet II, Src: 00:00:00_00:00:00 (00:00:00:00:00:00), Dst: 00:00:00_00:00:00 (00:00:00:00:00:00)
    Destination: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Source: 00:00:00_00:00:00 (00:00:00:00:00:00)
        Address: 00:00:00_00:00:00 (00:00:00:00:00:00)
        .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
    Type: IPv6 (0x86dd)
Internet Protocol Version 6, Src: ::1 (::1), Dst: ::1 (::1)
    0110 .... = Version: 6
        [0110 .... = This field makes the filter "ip.version == 6" possible: 6]
    .... 0000 0000 .... .... .... .... .... = Traffic class: 0x00000000
        .... 0000 00.. .... .... .... .... .... = Differentiated Services Field: Default (0x00000000)
        .... .... ..0. .... .... .... .... .... = ECN-Capable Transport (ECT): Not set
        .... .... ...0 .... .... .... .... .... = ECN-CE: Not set
    .... .... .... 0000 0000 0000 0000 0000 = Flowlabel: 0x00000000
    Payload length: 40
    Next header: TCP (0x06)
    Hop limit: 64
    Source: ::1 (::1)
    Destination: ::1 (::1)
Transmission Control Protocol, Src Port: netview-aix-5 (1665), Dst Port: navisphere (2162), Seq: 0, Len: 0
    Source port: netview-aix-5 (1665)
    Destination port: navisphere (2162)
    [Stream index: 3374]
    Sequence number: 0    (relative sequence number)
    Header length: 40 bytes
    Flags: 0x02 (SYN)
        000. .... .... = Reserved: Not set
        ...0 .... .... = Nonce: Not set
        .... 0... .... = Congestion Window Reduced (CWR): Not set
        .... .0.. .... = ECN-Echo: Not set
        .... ..0. .... = Urgent: Not set
        .... ...0 .... = Acknowledgement: Not set
        .... .... 0... = Push: Not set
        .... .... .0.. = Reset: Not set
        .... .... ..1. = Syn: Set
            [Expert Info (Chat/Sequence): Connection establish request (SYN): server port navisphere]
        .... .... ...0 = Fin: Not set
    Window size value: 32752
    [Calculated window size: 32752]
    Checksum: 0xebbf [validation disabled]
        [Good Checksum: False]
        [Bad Checksum: False]
    Options: (20 bytes)
        Maximum segment size: 16376 bytes
        TCP SACK Permitted Option: True
        Timestamps: TSval 1589502, TSecr 0
        No-Operation (NOP)
        Window scale: 7 (multiply by 128)

iptables-save เอาท์พุท:

# Generated by iptables-save v1.3.0 on Thu Jun 26 10:15:33 2014
*filter
:FORWARD ACCEPT [0:0]
:INPUT ACCEPT [675:236200]
:OUTPUT ACCEPT [241:21540]
COMMIT
# Completed on Thu Jun 26 10:15:33 2014

— Carolinian
แหล่งที่มา

ซ็อกเก็ตจากไคลเอ็นต์อยู่ในโหมดไม่บล็อกหรือไม่ เป็นไปได้ไหมว่าซ็อกเก็ตไคลเอ็นต์จะถูกปิดตามเวลาที่เซิร์ฟเวอร์ยอมรับ คุณมีการกำหนดเวลาสำหรับแพ็กเก็ตเหล่านั้นหรือไม่ pcap อาจจะ?

— Stéphane Chazelas

คุณตรวจสอบค่าตอบแทนของconnect()s? เป็นไปได้ไหมที่คุณไม่บล็อกสองช่องconnect()sบนซ็อกเก็ตเดียวกัน? เป็นไปได้หรือไม่ที่ลูกค้าบางรายถูกฆ่าหรือถูกขัดจังหวะในทางใดทางalarm()หนึ่งconnect()? คุณสามารถสร้างมันขึ้นมาใหม่ได้ด้วยไคลเอนต์ที่ทำงานภายใต้strace -ffหรือautrace?

— Stéphane Chazelas

มีอะไรแฟนซี (nfqueue, การ จำกัด การเชื่อมต่อ ... ) ในผลลัพธ์ของiptables-save? ความเป็นไปได้ที่ถึงขีด จำกัด ของทรัพยากรบ้างไหม? มีลูกค้าพร้อมกันกี่คน ทำสิ่งเหล่านั้นbindกับพอร์ตต้นทางเฉพาะหรือไม่?

— Stéphane Chazelas

จะเพิ่มคำถามให้ดีขึ้น คำถามมีมากขึ้นไม่ว่าจะเป็นข้อ จำกัด ในการทดสอบของคุณหรือมากกว่าที่เป็นจริง

— Stéphane Chazelas

ฉันเดาว่าความเครียดที่วางลงบนสแต็กจะมีการเชื่อมต่อหนึ่งครั้งในฝั่งไคลเอ็นต์หมดเวลาเมื่อครึ่งสถานะเปิด การเชื่อมต่อนั้นถูกดร็อป (ซึ่งหมายความว่าแอปไคลเอนต์ควรเห็นว่าเป็นกETIMEDOUT) และเมื่อสแตก / ack ถูกประมวลผลในที่สุดโดยสแต็กจะไม่มีการเชื่อมต่ออีกต่อไปที่เกี่ยวข้องกับมันและทำให้ได้รับการรีเซ็ต คุณลองเพิ่มขนาดของ backlog ( sysctl -w net.ipv4.tcp_max_syn_backlog=???) หรือไม่?

— didierc