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Message 1 of 15
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Accessing Internet from Linux Box

Hi all,

I have just had Virgin installed – Vivid 200 and SH3. Speedtests from Windows 10 machine give good results (200 up and 12 down). Linux box has 2 HDD, one with Ubuntu 15.10 and the other with Ubuntu 16.04LTS. Booting to Ubuntu 15.10 allows me to access the SH3 but not the outside world, this being on either WiFi or cabled. Booting to Ubuntu 16.04LTS allows me to access the SH3 and internet. However the Speedtest results are abysmally slow. As with Ubuntu 15.10 this is on both WiFi and cabled. Both boxes and OSes are completely up to date. No problems experienced with my previous ISP.

Anyone got any ideas?

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twin--turbo
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Message 12 of 15
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Re: Accessing Internet from Linux Box

The only thing I can think of is that an MTU is set too high on the laptop. Mine is set at 1500.

 

try

ping -s 1472 www.google.com

With packet headers that sets the packet at 1500

ping -s 1473 www.google.com

If that fails with payload = 1501 then it points to the MTU.

 

TT

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twin--turbo
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Message 2 of 15
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Re: Accessing Internet from Linux Box

Output of

"ip addr"

"traceroute 8.8.8.8"

"traceroute www.google.com"

"ping 192.168.0.1"
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Re: Accessing Internet from Linux Box

Hi,

Thanks for your response.

ip addr generates

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default
link/loopback **:**:**:**:**:** brd **:**:**:**:**:**
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc mq state DOWN group default qlen 1000
link/ether **:**:**:**:**:** brd **:**:**:**:**:**
3: wlx000f55a8302f: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether **:**:**:**:**:** brd **:**:**:**:**:**
inet 192.168.0.14/24 brd 192.168.0.255 scope global dynamic wlx000f55a8302f
valid_lft 80463sec preferred_lft 80463sec
inet6 fe80::20f:55ff:fea8:302f/64 scope link
valid_lft forever preferred_lft forever

Traceroute 8.8.8.8 generates

traceroute to 8.8.8.8 (8.8.8.8), 30 hops max, 60 byte packets
1 192.168.0.1 (192.168.0.1) 25.783 ms 27.447 ms 29.068 ms
2 * * *
3 bmly-core-2a-xe-200-0.network.virginmedia.net (80.1.224.225) 52.855 ms 53.064 ms 53.019 ms
4 * * *
5 eislou2-ic-1-ae3-0.network.virginmedia.net (62.254.85.145) 57.855 ms 66.518 ms 66.528 ms
6 m350-mp2.cvx3-a.ltn.dial.ntli.net (213.104.85.94) 66.365 ms 213.104.85.90 (213.104.85.90) 23.646 ms 29.947 ms
7 216.239.54.221 (216.239.54.221) 27.006 ms 72.14.237.47 (72.14.237.47) 36.616 ms 216.239.54.233 (216.239.54.233) 35.711 ms
8 209.85.246.65 (209.85.246.65) 38.024 ms 216.239.57.71 (216.239.57.71) 38.555 ms 216.239.57.159 (216.239.57.159) 267.470 ms
9 google-public-dns-a.google.com (8.8.8.8) 44.630 ms 38.951 ms 26.486 ms

Tracerout www.google.com generates

traceroute to www.google.com (216.58.198.164), 30 hops max, 60 byte packets
1 192.168.0.1 (192.168.0.1) 6.538 ms 8.195 ms 8.780 ms
2 * * *
3 bmly-core-2a-xe-200-0.network.virginmedia.net (80.1.224.225) 27.924 ms 28.080 ms 29.904 ms
4 * * *
5 eislou2-ic-1-ae3-0.network.virginmedia.net (62.254.85.145) 44.465 ms 44.757 ms 44.660 ms
6 m350-mp2.cvx3-a.ltn.dial.ntli.net (213.104.85.94) 43.240 ms 27.046 ms 213.104.85.90 (213.104.85.90) 30.597 ms
7 72.14.237.47 (72.14.237.47) 31.640 ms 31.332 ms 216.239.54.245 (216.239.54.245) 33.663 ms
8 108.170.232.97 (108.170.232.97) 31.979 ms 108.170.232.99 (108.170.232.99) 40.669 ms 39.442 ms
9 lhr25s10-in-f164.1e100.net (216.58.198.164) 37.670 ms 37.824 ms 24.487 ms

and pinging the SH3 is OK but in the case of 5 pings gives

PING 192.168.0.1 (192.168.0.1) 56(84) bytes of data.
64 bytes from 192.168.0.1: icmp_seq=1 ttl=64 time=9.13 ms
64 bytes from 192.168.0.1: icmp_seq=2 ttl=64 time=6.86 ms
64 bytes from 192.168.0.1: icmp_seq=3 ttl=64 time=4.89 ms
64 bytes from 192.168.0.1: icmp_seq=4 ttl=64 time=5.63 ms
64 bytes from 192.168.0.1: icmp_seq=5 ttl=64 time=7.14 ms

Is this a help in solving the problem?

Thanks for your interest.

 

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Message 4 of 15
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Re: Accessing Internet from Linux Box

Should have said that all above info. is via. Ubuntu 16.04LTS over wireless connection.
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Message 5 of 15
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Re: Accessing Internet from Linux Box

The above would suggest that all is ok with the broadband connection in terms of TCP/IP transit.

try the text based shell browser.

w3m  www.google.co.uk

 

 

and output of the local firewall

iptables -L

 

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Message 6 of 15
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Re: Accessing Internet from Linux Box

and

echo $http_proxy

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Message 7 of 15
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Re: Accessing Internet from Linux Box


w3m runs fine under 16.04LTS but is not installed under 15.10 and as I cannot get to the outside world from 15.10 I cannot install it
Am puzzled by the vast difference in the iptables output. Am at the experimental stage with Linux so it looks as if I have gone very wrong somewhere, the question being where and how.
No http proxies in use so no output from the echo command under either OS.
iptables output from both versions of the OS is as follows

16.04 LTS

iptables -L

Chain INPUT (policy DROP)
target prot opt source destination
ufw-before-logging-input all -- anywhere anywhere
ufw-before-input all -- anywhere anywhere
ufw-after-input all -- anywhere anywhere
ufw-after-logging-input all -- anywhere anywhere
ufw-reject-input all -- anywhere anywhere
ufw-track-input all -- anywhere anywhere

Chain FORWARD (policy DROP)
target prot opt source destination
ufw-before-logging-forward all -- anywhere anywhere
ufw-before-forward all -- anywhere anywhere
ufw-after-forward all -- anywhere anywhere
ufw-after-logging-forward all -- anywhere anywhere
ufw-reject-forward all -- anywhere anywhere
ufw-track-forward all -- anywhere anywhere

Chain OUTPUT (policy ACCEPT)
target prot opt source destination
ufw-before-logging-output all -- anywhere anywhere
ufw-before-output all -- anywhere anywhere
ufw-after-output all -- anywhere anywhere
ufw-after-logging-output all -- anywhere anywhere
ufw-reject-output all -- anywhere anywhere
ufw-track-output all -- anywhere anywhere

Chain ufw-after-forward (1 references)
target prot opt source destination

Chain ufw-after-input (1 references)
target prot opt source destination
ufw-skip-to-policy-input udp -- anywhere anywhere udp dpt:netbios-ns
ufw-skip-to-policy-input udp -- anywhere anywhere udp dpt:netbios-dgm
ufw-skip-to-policy-input tcp -- anywhere anywhere tcp dpt:netbios-ssn
ufw-skip-to-policy-input tcp -- anywhere anywhere tcp dpt:microsoft-ds
ufw-skip-to-policy-input udp -- anywhere anywhere udp dpt:bootps
ufw-skip-to-policy-input udp -- anywhere anywhere udp dpt:bootpc
ufw-skip-to-policy-input all -- anywhere anywhere ADDRTYPE match dst-type BROADCAST

Chain ufw-after-logging-forward (1 references)
target prot opt source destination
LOG all -- anywhere anywhere limit: avg 3/min burst 10 LOG level warning prefix "[UFW BLOCK] "

Chain ufw-after-logging-input (1 references)
target prot opt source destination
LOG all -- anywhere anywhere limit: avg 3/min burst 10 LOG level warning prefix "[UFW BLOCK] "

Chain ufw-after-logging-output (1 references)
target prot opt source destination

Chain ufw-after-output (1 references)
target prot opt source destination

Chain ufw-before-forward (1 references)
target prot opt source destination
ACCEPT all -- anywhere anywhere ctstate RELATED,ESTABLISHED
ACCEPT icmp -- anywhere anywhere icmp destination-unreachable
ACCEPT icmp -- anywhere anywhere icmp source-quench
ACCEPT icmp -- anywhere anywhere icmp time-exceeded
ACCEPT icmp -- anywhere anywhere icmp parameter-problem
ACCEPT icmp -- anywhere anywhere icmp echo-request
ufw-user-forward all -- anywhere anywhere

Chain ufw-before-input (1 references)
target prot opt source destination
ACCEPT all -- anywhere anywhere
ACCEPT all -- anywhere anywhere ctstate RELATED,ESTABLISHED
ufw-logging-deny all -- anywhere anywhere ctstate INVALID
DROP all -- anywhere anywhere ctstate INVALID
ACCEPT icmp -- anywhere anywhere icmp destination-unreachable
ACCEPT icmp -- anywhere anywhere icmp source-quench
ACCEPT icmp -- anywhere anywhere icmp time-exceeded
ACCEPT icmp -- anywhere anywhere icmp parameter-problem
ACCEPT icmp -- anywhere anywhere icmp echo-request
ACCEPT udp -- anywhere anywhere udp spt:bootps dpt:bootpc
ufw-not-local all -- anywhere anywhere
ACCEPT udp -- anywhere 224.0.0.251 udp dpt:mdns
ACCEPT udp -- anywhere 239.255.255.250 udp dpt:1900
ufw-user-input all -- anywhere anywhere

Chain ufw-before-logging-forward (1 references)
target prot opt source destination

Chain ufw-before-logging-input (1 references)
target prot opt source destination

Chain ufw-before-logging-output (1 references)
target prot opt source destination

Chain ufw-before-output (1 references)
target prot opt source destination
ACCEPT all -- anywhere anywhere
ACCEPT all -- anywhere anywhere ctstate RELATED,ESTABLISHED
ufw-user-output all -- anywhere anywhere

Chain ufw-logging-allow (0 references)
target prot opt source destination
LOG all -- anywhere anywhere limit: avg 3/min burst 10 LOG level warning prefix "[UFW ALLOW] "

Chain ufw-logging-deny (2 references)
target prot opt source destination
RETURN all -- anywhere anywhere ctstate INVALID limit: avg 3/min burst 10
LOG all -- anywhere anywhere limit: avg 3/min burst 10 LOG level warning prefix "[UFW BLOCK] "

Chain ufw-not-local (1 references)
target prot opt source destination
RETURN all -- anywhere anywhere ADDRTYPE match dst-type LOCAL
RETURN all -- anywhere anywhere ADDRTYPE match dst-type MULTICAST
RETURN all -- anywhere anywhere ADDRTYPE match dst-type BROADCAST
ufw-logging-deny all -- anywhere anywhere limit: avg 3/min burst 10
DROP all -- anywhere anywhere

Chain ufw-reject-forward (1 references)
target prot opt source destination

Chain ufw-reject-input (1 references)
target prot opt source destination

Chain ufw-reject-output (1 references)
target prot opt source destination

Chain ufw-skip-to-policy-forward (0 references)
target prot opt source destination
DROP all -- anywhere anywhere

Chain ufw-skip-to-policy-input (7 references)
target prot opt source destination
DROP all -- anywhere anywhere

Chain ufw-skip-to-policy-output (0 references)
target prot opt source destination
ACCEPT all -- anywhere anywhere

Chain ufw-track-forward (1 references)
target prot opt source destination

Chain ufw-track-input (1 references)
target prot opt source destination

Chain ufw-track-output (1 references)
target prot opt source destination
ACCEPT tcp -- anywhere anywhere ctstate NEW
ACCEPT udp -- anywhere anywhere ctstate NEW

Chain ufw-user-forward (1 references)
target prot opt source destination

Chain ufw-user-input (1 references)
target prot opt source destination

Chain ufw-user-limit (0 references)
target prot opt source destination
LOG all -- anywhere anywhere limit: avg 3/min burst 5 LOG level warning prefix "[UFW LIMIT BLOCK] "
REJECT all -- anywhere anywhere reject-with icmp-port-unreachable

Chain ufw-user-limit-accept (0 references)
target prot opt source destination
ACCEPT all -- anywhere anywhere

Chain ufw-user-logging-forward (0 references)
target prot opt source destination

Chain ufw-user-logging-input (0 references)
target prot opt source destination

Chain ufw-user-logging-output (0 references)
target prot opt source destination

Chain ufw-user-output (1 references)
target prot opt source destination

15.10

Chain INPUT (policy ACCEPT)
target prot opt source destination

Chain FORWARD (policy ACCEPT)
target prot opt source destination

Chain OUTPUT (policy ACCEPT)
target prot opt source destination

Once again thanks for your interest and help.
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Message 8 of 15
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Re: Accessing Internet from Linux Box

The difference is that 16.04 has UFW setting up the firewall rules and 15.10 is not using any (TBH  I have never run the firewall at home on my Linux machines)

I don't think it's the problem though.

sudo ufw disable ( would disable it though).

If w3m can browse then the machine is configured correctly, it must be an issue with your desktop browser.

Can you install something from "Software Manager"?

If your running firefox I would check Advanced Settings.

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Message 9 of 15
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Re: Accessing Internet from Linux Box

Checked 15.10 and ufw inactive. Enabled it and ran iptables -L. Output identical to that from 16.04. Tried FireFox Ver. 47 and Chrome Ver. 53 on 15.10 when problem arose. Appears to be a DNS problem as both browsers fail to resolve any URL. Firefox reports Server not found and Chrome reports This site can't be reached ERR_NAME_RESOLUTION_FAILED. Yet both browsers work, albeit very slow speedtest results, under 16.04
Have checked connection details under both OSes and they are identical. Advanced settings under both seem to be OK too. As I cannot access package downloads via. Synaptic or Ubuntu Software Centre from 15.10 I'm a bit stuck.
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Message 10 of 15
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Re: Accessing Internet from Linux Box

have you tried removing and re-adding the connection in network control pannel and having it on full DHCP to get DNS settings from the router?

TT
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