Domain access (ping) from outside server and not from inside

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#1 Tue, 12/10/2019 - 08:13
Prx

Domain access (ping) from outside server and not from inside

hi, I am on a VPS, have Virtualmin with some domains of my own.

For some time, I mentioned that internal processes cannot see their own domain. Let us take the domain yanfouom.net : you can reach it from anywhere by a ping, but not when I am connected in a terminal on the VPS ! I made a mistake somewhere. Can you please help me ? Thanks per advance. Here are some facts :

In a terminal on the server, you type :

x@vps296125:~$ ping yanfouom.net

you get:

PING yanfouom.net (51.255.197.10) 56(84) bytes of data.
^C
--- yanfouom.net ping statistics ---
7 packets transmitted, 0 received, 100% packet loss, time 6047ms"

If I type the command : >netstat -taupen | grep 53 I get :

tcp        0      0 0.0.0.0:465             0.0.0.0:*               LISTEN      0          12537       -              
tcp        0      0 51.255.197.10:53        0.0.0.0:*               LISTEN      107        11070       -              
tcp        0      0 127.0.0.1:53            0.0.0.0:*               LISTEN      107        11047       -              
tcp        0      0 0.0.0.0:25              0.0.0.0:*               LISTEN      0          12531       -              
tcp        0      0 127.0.0.1:953           0.0.0.0:*               LISTEN      107        11320       -              
tcp6       0      0 :::465                  :::*                    LISTEN      0          12538       -              
tcp6       0      0 :::53                   :::*                    LISTEN      107        10998       -              
tcp6       0      0 :::25                   :::*                    LISTEN      0          12532       -              
udp        0      0 51.255.197.10:53        0.0.0.0:*                           107        11069       -              
udp        0      0 127.0.0.1:53            0.0.0.0:*                           107        11046       -              
udp6       0      0 :::53                   :::*                                107        10997       -
Thu, 12/12/2019 - 07:21
Prx

Any clue / idea where to look ? Thks !

William

Thu, 12/12/2019 - 15:52
Dibs

Assuming you are using iptables - have you "blocked" ICMP?

https://vitux.com/how-to-block-allow-ping-using-iptables-in-ubuntu/

Fri, 12/13/2019 - 00:33
Prx

thank you for your idea / suggestion, No I do not have such line in iptables. I tested without some lines. Fail2bain removed also is not the solution. I tested the server in rescue mode (without the firewall mainly) and it works , but in "normal" mode it does not. It shoud come from elsewhere.

William

Fri, 12/13/2019 - 05:45
Prx

I saw by iptable -L that I had a problem, I removed that line and all is correct - thanks to all !

William

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