Missing ARP Reply

Installing and Using OpenWrt
1

Hello,
when using tcpdump over my dsl interface I can see ARP requests looking for Gateway MAC Address but I can't get reply

23:30:30.554185 c8:77:65:10:60:d0 (oui Unknown) > Broadcast, ethertype ARP (0x0806), length 42: Ethernet (len 6), IPv4 (len 4), Request who-has 2.1.1.2 tell 2.1.1.1, length 28

Meanwhile, I'm ping from outside and I can see the ICMP packets incoming, so I think the gateway is up and running

23:30:32.182165 84:c1:c1:7d:46:9b (oui Unknown) > c8:77:65:10:60:d5 (oui Unknown), ethertype IPv4 (0x0800), length 74: (tos 0x0, ttl 125, id 7255, offset 0, flags [none], proto ICMP (1), length 60)
    6.7.8.9 > 2.1.1.1: ICMP echo request, id 1, seq 257, length 40

Any suggestions ?

2

Do you have some problem from the missing arp or you just think that something is wrong?
FYI arp is not a protocol used in dsl.

3

I can't ping the gateway so I started dump network traffic

4

And you sure it's pingable? Unfortunately, lots of Internet nodes reject ICMP.

5

Do you mean your regular Ethernet interface that is connected to your DSL modem or something else?

6

Yes, using the original provider's router it is pingable

1 Like
7

I'm using tcpdump -i dsl0, this is the DSL interface of my router

8

This is the configuration

config dsl 'dsl'
        option tone 'av'
        option xfer_mode 'ptm'
        option line_mode 'vdsl'
        option ds_snr_offset '0'
        option firmware '/lib/firmware/lantiq-vrx200-b.bin'
        option annex 'b'
        option vid '835'
        option type '8021q'

config interface 'wan'
        option proto 'static'
        option gateway 2.1.1.2'
        list ipaddr '2.1.1.1/30'
        option device 'dsl0.835'

config device
        option type '8021q'
        option ifname 'dsl0'
        option vid '835'
        option name 'dsl0.835'
        option mtu '1500'
        option macaddr 'C8:77:65:10:60:D0'
        option ipv6 '0'

My provider is using VLAN 835