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LAST BREAKTHROUGH -> search the tshark results below for a possible cause of the problem
Hi, at home I have the following setup:
Internet - NAS (Ubuntu 16.04.4 LTS) - LAN (Asus N56U WiFi) - family users. NAS connects using pppoe (ppp0, cable) to Internet while having eth0 (192.168.0.1, cable) to LAN. Asus N56U connects to NAS using static ip 192.168.0.2/255.255.255.0 with DNS 192.168.0.1.
Everything works fine:
NAS & family users access the Internet while Internet access NAS.
I also have another extremely similar router (Asus RT-AC66U) which simply swapping with Asus N56U while keeping same simple settings doesn't work . I mean anything that touches the Internet dies though my personal web sites are still accessible from LAN.
I tried this command on NAS (108.177.119.94 is www.google.ro):
Code:
sudo tcpdump -vv -i eth0 --direction=in -n ip proto \\icmp
while on RT-AC66U (with telnet access) I execute this:
$sudo tcpdump -vv -i eth0 --direction=in -n ip proto \\icmp
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
20:33:57.279728 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto ICMP (1), length 84)
192.168.0.2 > 172.217.17.36: ICMP echo request, id 15109, seq 0, length 64
20:36:56.759155 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto ICMP (1), length 84)
192.168.0.2 > 172.217.17.35: ICMP echo request, id 44293, seq 0, length 64
...
while on RT-AC66U I get 100% ping loss.
When RT-AC66U is pinging NAS:
Code:
ping -c 1 -s 1472 -I eth0 192.168.0.1
I have 100% ping success (max MTU is 1472).
Also RT-AC66U clearly shows in its admin interface that has Internet access but all (browser, ping) that touch the Internet fails.
What could be the problem or how could I further troubleshoot this?
EDIT
With the command:
Code:
ping -c 1 www.google.ro
I get (there's also a NTP service running on router):
Code:
$sudo tcpdump -vv --direction=inout -n
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
09:31:08.734787 IP (tos 0x0, ttl 64, id 54539, offset 0, flags [DF], proto UDP (17), length 59)
192.168.0.2.45945 > 192.168.0.1.53: [udp sum ok] 2+ AAAA? www.google.ro. (31)
09:31:08.735222 IP (tos 0x0, ttl 64, id 51978, offset 0, flags [DF], proto UDP (17), length 87)
192.168.0.1.53 > 192.168.0.2.45945: [udp sum ok] 2 q: AAAA? www.google.ro. 1/0/0 www.google.ro. AAAA 2a00:1450:4005:800::2003 (59)
09:31:08.735692 IP (tos 0x0, ttl 64, id 54539, offset 0, flags [DF], proto UDP (17), length 59)
192.168.0.2.49395 > 192.168.0.1.53: [udp sum ok] 3+ A? www.google.ro. (31)
09:31:08.736093 IP (tos 0x0, ttl 64, id 51979, offset 0, flags [DF], proto UDP (17), length 75)
192.168.0.1.53 > 192.168.0.2.49395: [udp sum ok] 3 q: A? www.google.ro. 1/0/0 www.google.ro. A 172.217.16.67 (47)
09:31:08.737265 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto ICMP (1), length 84)
192.168.0.2 > 172.217.16.67: ICMP echo request, id 49922, seq 0, length 64
09:31:09.084884 IP (tos 0x0, ttl 64, id 54574, offset 0, flags [DF], proto UDP (17), length 62)
192.168.0.2.54246 > 192.168.0.1.53: [udp sum ok] 2+ A? dns.msftncsi.com. (34)
09:31:09.085301 IP (tos 0x0, ttl 64, id 52022, offset 0, flags [DF], proto UDP (17), length 78)
192.168.0.1.53 > 192.168.0.2.54246: [udp sum ok] 2 q: A? dns.msftncsi.com. 1/0/0 dns.msftncsi.com. A 131.107.255.255 (50)
09:31:14.081697 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.0.1 tell 192.168.0.2, length 46
09:31:14.081787 ARP, Ethernet (len 6), IPv4 (len 4), Reply 192.168.0.1 is-at d0:50:99:7c:28:bf, length 28
09:31:14.084774 IP (tos 0x0, ttl 64, id 55074, offset 0, flags [DF], proto UDP (17), length 62)
192.168.0.2.56118 > 192.168.0.1.53: [udp sum ok] 2+ A? dns.msftncsi.com. (34)
09:31:14.085194 IP (tos 0x0, ttl 64, id 52668, offset 0, flags [DF], proto UDP (17), length 78)
192.168.0.1.53 > 192.168.0.2.56118: [udp sum ok] 2 q: A? dns.msftncsi.com. 1/0/0 dns.msftncsi.com. A 131.107.255.255 (50)
09:31:19.084681 IP (tos 0x0, ttl 64, id 55574, offset 0, flags [DF], proto UDP (17), length 62)
192.168.0.2.48848 > 192.168.0.1.53: [udp sum ok] 2+ A? dns.msftncsi.com. (34)
09:31:19.088817 IP (tos 0x0, ttl 64, id 52778, offset 0, flags [DF], proto UDP (17), length 78)
192.168.0.1.53 > 192.168.0.2.48848: [udp sum ok] 2 q: A? dns.msftncsi.com. 1/0/0 dns.msftncsi.com. A 131.107.255.255 (50)
^C
13 packets captured
13 packets received by filter
0 packets dropped by kernel
I have for the NAS/ppp0 interface the ip 188.25.28.84. Running:
Code:
ping 188.25.28.84
has 100% success so I guess NAS/eth0 is indeed passing further the ping requests.
With everything the same, just replacing the RT-AC66U router with N56U router I get (for same ping command):
Code:
$sudo tcpdump -vv --direction=inout -n
tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
09:42:49.938781 IP (tos 0x0, ttl 64, id 46253, offset 0, flags [DF], proto UDP (17), length 59)
192.168.0.2.43709 > 192.168.0.1.53: [udp sum ok] 2+ AAAA? www.google.ro. (31)
09:42:49.939220 IP (tos 0x0, ttl 64, id 32438, offset 0, flags [DF], proto UDP (17), length 87)
192.168.0.1.53 > 192.168.0.2.43709: [udp sum ok] 2 q: AAAA? www.google.ro. 1/0/0 www.google.ro. AAAA 2a00:1450:400e:801::2003 (59)
09:42:49.940179 IP (tos 0x0, ttl 64, id 46253, offset 0, flags [DF], proto UDP (17), length 59)
192.168.0.2.40809 > 192.168.0.1.53: [udp sum ok] 3+ A? www.google.ro. (31)
09:42:49.943623 IP (tos 0x0, ttl 64, id 32439, offset 0, flags [DF], proto UDP (17), length 75)
192.168.0.1.53 > 192.168.0.2.40809: [udp sum ok] 3 q: A? www.google.ro. 1/0/0 www.google.ro. A 216.58.212.163 (47)
09:42:49.944931 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto ICMP (1), length 84)
192.168.0.2 > 216.58.212.163: ICMP echo request, id 20227, seq 0, length 64
09:42:49.984249 IP (tos 0xc, ttl 55, id 0, offset 0, flags [none], proto ICMP (1), length 84)
216.58.212.163 > 192.168.0.2: ICMP echo reply, id 20227, seq 0, length 64
^C
6 packets captured
6 packets received by filter
0 packets dropped by kernel
The UFW log has nothing for this ping command. It's odd the fact that is not working the internet access while same configuration works for the N56U router, an Asus too, with same configuration options & interface.
Last edited by adrhc; 05-12-2018 at 08:35 AM.
Reason: announcing last finding
The two models ought to be very similar and ought to have almost exact same Asus OS.
That makes me think it isn't the router but you will have to prove this router will work like you wish.
My feeling is I'd look to the server and see if you set any settings in it for mac address or leases.
I would agree with you there's some wrong configuration on NAS but see EDIT2: only swapping RT-AC66U with N56U makes things working.
I have default configuration for mac (both NAS and routers) while there's no DHCP lease because I use a static ip for the router's WAN configuration.
So the question is if the router is at fault or something else.
Can you test the router in the configuration that you wish to run it outside of your setup?
There are logs and network tools in each of the routers. The web based config ought to be almost identical. Maybe some variation in options. This one isn't a T-mobile branded router is it?
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).
Considering the routers to be very similar (same company, same configuration options) and the entire context the same (I'm just swapping the routers) I guess the only difference should be between the above request, but what possibly could be?
PS: I'm on AC66U while writing these; RDP also works fine
Last edited by adrhc; 05-05-2018 at 07:59 AM.
Reason: typo
Just swapping the routers makes things work so I don't know. The configuration is exactly the same for both routers - easy task to do when the GUI is the same. Anyway, what kind of issue do you think might happen?
They could share the same basic version of the ASWRT OS but each device may have a few unique features. I'd think it more of a basic networking setting over any added feature. Would be nice to be on same level I'd guess.
Might even be able to set the settings from working to non-working model.
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internet access with ping has 100% loss
. I mean anything that touches the Internet dies though my personal web sites are still accessible from LAN.
). Also is working fine; right now is directly connected to internet using pppoe (I installed it in another location).
