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I have a ethernet cable connection to my university's network, and I've been using it regularly and without a problem for months now. 2 days ago suddenly it stopped working. now I can only access subdomains of the website *.ut.ac.ir and ut.ac.ir except the login page which is internet.ut.ac.ir

when I use ping on internet.ut.ac.ir it says destination host unreachable. But this happens only on my linux mint operating system. I have windows and ubuntu too, and those are working smoothly and as expected.

any help would be appreciated.

EDIT 1: I ran a traceroute on internet.ut.ac.ir and ems.ut.ac.ir and here is the result:

traceroute internet.ut.ac.ir traceroute to internet.ut.ac.ir (172.17.49.2), 30 hops max, 60 byte packets  
1  arianhf-Lenovo-Z50-70 (172.17.0.1)  725.530 ms !H  725.507 ms !H  725.493 ms !H

traceroute ems.ut.ac.ir     
traceroute to ems.ut.ac.ir (192.168.112.132), 30 hops max, 60 byte packets
 1  _gateway (172.18.47.129)  0.385 ms  0.781 ms  0.957 ms
 2  192.168.40.1 (192.168.40.1)  1.063 ms  1.132 ms  1.191 ms
 3  * * *
 4  * * *
...
29  * * *
30  * * *

EDIT 2: this is the output of the command when I use university network:

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         172.18.47.129   0.0.0.0         UG    100    0        0 enp1s0
169.254.0.0     0.0.0.0         255.255.0.0     U     1000   0        0 docker0
172.17.0.0      0.0.0.0         255.255.0.0     U     0      0        0 docker0
172.18.47.128   0.0.0.0         255.255.255.192 U     100    0        0 enp1s0

this is the output of the same command connected to my phone with USB

Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         172.20.10.1     0.0.0.0         UG    100    0        0 enp0s20u3c4i2
169.254.0.0     0.0.0.0         255.255.0.0     U     1000   0        0 docker0
172.17.0.0      0.0.0.0         255.255.0.0     U     0      0        0 docker0
172.20.10.0     0.0.0.0         255.255.255.240 U     100    0        0 enp0s20u3c4i2
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At the first check iptables or firewall on your mint linux. Next check the network routes and the last thing you should test is DNS resolving server configuration.

  • ok, so how should i do that? what should I look for? – arianhf Jul 8 '19 at 5:14
  • @arianhf Do you ping reply on windows? – P.Goli Jul 8 '19 at 13:48
  • I added some more info, also I have turned all kinds of firewalls off @P.Goli – arianhf Jul 13 '19 at 7:08
  • @arianhf Would you please copy the output of route -n command? – P.Goli Jul 15 '19 at 13:40
  • I added that info as an edit. – arianhf Jul 16 '19 at 9:39

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