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  1. #1

    internet access with ping has 100% loss


    I have at home the following setup:
    Internet - NAS (Ubuntu 16.04.4 LTS) - LAN (Asus N56U wireless router) - family users
    NAS connects using pppoe (ppp0, UTP cable) to Internet while having eth0 (192.168.0.1, UTP cable) for LAN.
    Asus N56U connects to NAS using static ip 192.168.0.2 with DNS 192.168.0.1.
    Everything works fine: NAS (cable) and family users (WiFi) access the Internet.
    I use the same setup with Asus RT-AC66U and simply doesn't work .
    In order to troubleshoot this I run on NAS (108.177.119.94 is google):
    Code:
    sudo tcpdump -AX -vnni eth0 -c 2 dst 108.177.119.94
    while running this on routers (I have telnet access to them):
    Code:
    ping -c 2 108.177.119.94
    I get (using tshark) this for N56U:
    Code:
    $tshark -r n56u-eth0-dst.pcap -V
    Frame 1: 98 bytes on wire (784 bits), 98 bytes captured (784 bits)
        Encapsulation type: Ethernet (1)
        Arrival Time: May  5, 2018 09:00:47.036839000 EEST
        [Time shift for this packet: 0.000000000 seconds]
        Epoch Time: 1525500047.036839000 seconds
        [Time delta from previous captured frame: 0.000000000 seconds]
        [Time delta from previous displayed frame: 0.000000000 seconds]
        [Time since reference or first frame: 0.000000000 seconds]
        Frame Number: 1
        Frame Length: 98 bytes (784 bits)
        Capture Length: 98 bytes (784 bits)
        [Frame is marked: False]
        [Frame is ignored: False]
        [Protocols in frame: eth:ethertype:ip:icmp:data]
    Ethernet II, Src: Motorola_1b:ed:f2 (98:0c:a5:1b:ed:f2), Dst: AsrockIn_7c:28:bf (d0:50:99:7c:28:bf)
        Destination: AsrockIn_7c:28:bf (d0:50:99:7c:28:bf)
            Address: AsrockIn_7c:28:bf (d0:50:99:7c:28:bf)
            .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
            .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        Source: Motorola_1b:ed:f2 (98:0c:a5:1b:ed:f2)
            Address: Motorola_1b:ed:f2 (98:0c:a5:1b:ed:f2)
            .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
            .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        Type: IPv4 (0x0800)
    Internet Protocol Version 4, Src: 192.168.0.2, Dst: 108.177.119.94
        0100 .... = Version: 4
        .... 0101 = Header Length: 20 bytes (5)
        Differentiated Services Field: 0x00 (DSCP: CS0, ECN: Not-ECT)
            0000 00.. = Differentiated Services Codepoint: Default (0)
            .... ..00 = Explicit Congestion Notification: Not ECN-Capable Transport (0)
        Total Length: 84
        Identification: 0x0000 (0)
        Flags: 0x02 (Don't Fragment)
            0... .... = Reserved bit: Not set
            .1.. .... = Don't fragment: Set
            ..0. .... = More fragments: Not set
        Fragment offset: 0
        Time to live: 64
        Protocol: ICMP (1)
        Header checksum: 0x95ef [validation disabled]
        [Header checksum status: Unverified]
        Source: 192.168.0.2
        Destination: 108.177.119.94
        [Source GeoIP: Unknown]
        [Destination GeoIP: United States, AS15169 Google Inc., Mountain View, CA, 37.419201, -122.057404]
            [Destination GeoIP Country: United States]
            [Destination GeoIP AS Number: AS15169 Google Inc.]
            [Destination GeoIP City: Mountain View, CA]
            [Destination GeoIP Latitude: 37.419201]
            [Destination GeoIP Longitude: -122.057404]
    Internet Control Message Protocol
        Type: 8 (Echo (ping) request)
        Code: 0
        Checksum: 0xd64a [correct]
        [Checksum Status: Good]
        Identifier (BE): 63814 (0xf946)
        Identifier (LE): 18169 (0x46f9)
        Sequence number (BE): 0 (0x0000)
        Sequence number (LE): 0 (0x0000)
        Data (56 bytes)
    
    0000  7c d9 ab 94 00 00 00 00 00 00 00 00 00 00 00 00   |...............
    0010  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
    0020  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
    0030  00 00 00 00 00 00 00 00                           ........
            Data: 7cd9ab940000000000000000000000000000000000000000...
            [Length: 56]
    and this for AC66U (the problematic one):
    Code:
    $tshark -r ac66u-eth0-dst.pcap -V
    Frame 1: 98 bytes on wire (784 bits), 98 bytes captured (784 bits)
        Encapsulation type: Ethernet (1)
        Arrival Time: May  5, 2018 09:07:16.655875000 EEST
        [Time shift for this packet: 0.000000000 seconds]
        Epoch Time: 1525500436.655875000 seconds
        [Time delta from previous captured frame: 0.000000000 seconds]
        [Time delta from previous displayed frame: 0.000000000 seconds]
        [Time since reference or first frame: 0.000000000 seconds]
        Frame Number: 1
        Frame Length: 98 bytes (784 bits)
        Capture Length: 98 bytes (784 bits)
        [Frame is marked: False]
        [Frame is ignored: False]
        [Protocols in frame: eth:ethertype:ip:icmp:data]
    Ethernet II, Src: AsustekC_cb:20:d0 (2c:56:dc:cb:20:d0), Dst: Broadcast (ff:ff:ff:ff:ff:ff)
        Destination: Broadcast (ff:ff:ff:ff:ff:ff)
            Address: Broadcast (ff:ff:ff:ff:ff:ff)
            .... ..1. .... .... .... .... = LG bit: Locally administered address (this is NOT the factory default)
            .... ...1 .... .... .... .... = IG bit: Group address (multicast/broadcast)
        Source: AsustekC_cb:20:d0 (2c:56:dc:cb:20:d0)
            Address: AsustekC_cb:20:d0 (2c:56:dc:cb:20:d0)
            .... ..0. .... .... .... .... = LG bit: Globally unique address (factory default)
            .... ...0 .... .... .... .... = IG bit: Individual address (unicast)
        Type: IPv4 (0x0800)
    Internet Protocol Version 4, Src: 192.168.0.2, Dst: 108.177.119.94
        0100 .... = Version: 4
        .... 0101 = Header Length: 20 bytes (5)
        Differentiated Services Field: 0x00 (DSCP: CS0, ECN: Not-ECT)
            0000 00.. = Differentiated Services Codepoint: Default (0)
            .... ..00 = Explicit Congestion Notification: Not ECN-Capable Transport (0)
        Total Length: 84
        Identification: 0x0000 (0)
        Flags: 0x02 (Don't Fragment)
            0... .... = Reserved bit: Not set
            .1.. .... = Don't fragment: Set
            ..0. .... = More fragments: Not set
        Fragment offset: 0
        Time to live: 64
        Protocol: ICMP (1)
        Header checksum: 0x95ef [validation disabled]
        [Header checksum status: Unverified]
        Source: 192.168.0.2
        Destination: 108.177.119.94
        [Source GeoIP: Unknown]
        [Destination GeoIP: United States, AS15169 Google Inc., Mountain View, CA, 37.419201, -122.057404]
            [Destination GeoIP Country: United States]
            [Destination GeoIP AS Number: AS15169 Google Inc.]
            [Destination GeoIP City: Mountain View, CA]
            [Destination GeoIP Latitude: 37.419201]
            [Destination GeoIP Longitude: -122.057404]
    Internet Control Message Protocol
        Type: 8 (Echo (ping) request)
        Code: 0
        Checksum: 0x638c [correct]
        [Checksum Status: Good]
        Identifier (BE): 27906 (0x6d02)
        Identifier (LE): 621 (0x026d)
        Sequence number (BE): 0 (0x0000)
        Sequence number (LE): 0 (0x0000)
        Data (56 bytes)
    
    0000  de 6b 49 05 00 00 00 00 00 00 00 00 00 00 00 00   .kI.............
    0010  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
    0020  00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00   ................
    0030  00 00 00 00 00 00 00 00                           ........
            Data: de6b49050000000000000000000000000000000000000000...
            [Length: 56]
    With N56U I see (using tcpdump) the request travelling from eth0 through ppp0 to Internet and back; with AC66U the above result is all I see (the request is received by eth0 then nothing).

    Please note that the routers are very similar (same company, same configuration options) and the entire context the same (I'm just swapping the routers).

    I guess the section (for AC66U):
    Code:
    Destination: Broadcast (ff:ff:ff:ff:ff:ff)
    might be the problem. If affirmative then why this happens and what is the solution?

    PS: I'm on AC66U (using pppoe) while writing these; RDP also works fine so with pppoe is fine
    Last edited by adrhc; 2 Weeks Ago at 10:53 AM. Reason: typo

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