3

want to access the MYSQL database remotely but when checking on yougetsignal(dot) com I get a message that port 3306 is closed.

Configuration: Fresh Server (Centos 6.4 64 bit with Zpanel installed)

Steps Already Taken:

  1. Removed bind address from my.cnf

  2. Tried adding bind address as server IP

  3. Have edited the IPTABLES to keep the port open.

  4. Forwarded the port from router

  5. added port=3306 in /etc/my.cnf

  6. Stopped IPTABLES

  7. several restarts of mysqld after every change

  8. restarts of IPTABLES after change

Nothing has worked so far.

IP Tables:

# Firewall configuration written by system-config-firewall
# Manual customization of this file is not recommended.
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 80 -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 3306 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT

Diagnostic Results: netstat result:

# netstat -na | grep 3306
tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN

netstat Results (netstat -lnp | grep mysql)

# netstat -lnp | grep mysql
tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 6684/mysqld
unix 2 [ ACC ] STREAM LISTENING 33101 6684/mysqld /var/lib/mysql/mysql.sock

iptables -L Results:

Chain INPUT (policy ACCEPT)
target prot opt source destination
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
ACCEPT icmp -- anywhere anywhere
ACCEPT all -- anywhere anywhere
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:ssh
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:http
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:https
ACCEPT tcp -- anywhere anywhere state NEW tcp dpt:mysql

Chain FORWARD (policy ACCEPT)
target prot opt source destination
REJECT all -- anywhere anywhere reject-with icmp-host-prohibited

Chain OUTPUT (policy ACCEPT)
target prot opt source destination

can run nc on server from localhost / SSH connection but not from remote systems

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10
  • 2
    What happens when from another system on the same LAN you do telnet server.ip.address 3306? Or is this, by any chance, a virtual server?
    – MadHatter
    Jul 9, 2014 at 11:12
  • It is a VPS so cannot do telnet from LAN
    – Amresh Singh
    Jul 9, 2014 at 11:15
  • Have you checked that the VPS host is not filtering traffic? Many do, and the fact that your firewall opens up port 22 yet I can't reach port 22 on your server makes me very suspicious that there's another firewall involved. (Congratulations on your investigations so far, it looks like you've been doing some thorough reading and digging.)
    – MadHatter
    Jul 9, 2014 at 11:16
  • Yeah have verified with the host and traffic is open
    – Amresh Singh
    Jul 9, 2014 at 11:18
  • 1
    Well, someone is filtering traffic to it; see my comment above about port 22. It still seems extremely likely to me that they are filtering somewhere in their network. You might want to ask them about port 22 traffic; if they say they're not filtering that, either, then you know they're not telling the truth.
    – MadHatter
    Jul 9, 2014 at 11:18

2 Answers 2

Reset to default
3

The traffic is likely being filtered.

Because you supplied your domain name (assuming here, that despite having two A records with two different addresses 141.101.117.86 is accurate..

Tracerouting to port 80, which we can demonstrably prove is open..

$ sudo traceroute -T -O info 141.101.117.86 -p 80
traceroute to 141.101.117.86 (141.101.117.86), 30 hops max, 60 byte packets
 1  192.168.1.1 (192.168.1.1)  0.332 ms  0.460 ms  0.574 ms
 2  host-92-25-242-1.as13285.net (92.25.242.1)  13.745 ms  13.807 ms  13.902 ms
 3  host-78-151-225-189.static.as13285.net (78.151.225.189)  15.058 ms  15.086 ms  15.118 ms
 4  host-78-151-225-196.static.as13285.net (78.151.225.196)  16.120 ms host-78-151-225-232.static.as13285.net (78.151.225.232)  15.748 ms host-78-151-225-184.static.as13285.net (78.151.225.184)  16.069 ms
 5  host-78-144-11-115.as13285.net (78.144.11.115)  16.630 ms  16.579 ms host-78-144-11-109.as13285.net (78.144.11.109)  16.798 ms
 6  195.66.225.179 (195.66.225.179)  16.728 ms  14.735 ms  14.707 ms
 7  141.101.117.86 (141.101.117.86) <syn,ack>  14.713 ms  14.907 ms  14.887 ms

If we try 3306..

$ sudo traceroute -T -O info 141.101.117.86 -p 3306
traceroute to 141.101.117.86 (141.101.117.86), 30 hops max, 60 byte packets
 1  192.168.1.1 (192.168.1.1)  0.343 ms  0.444 ms  0.624 ms
 2  host-92-25-242-1.as13285.net (92.25.242.1)  13.225 ms  13.226 ms  13.233 ms
 3  host-78-151-225-189.static.as13285.net (78.151.225.189)  14.736 ms  15.352 ms  15.347 ms
 4  host-78-151-225-220.static.as13285.net (78.151.225.220)  15.492 ms host-78-151-228-37.as13285.net (78.151.228.37)  15.441 ms host-78-151-225-232.static.as13285.net (78.151.225.232)  15.350 ms
 5  host-78-144-11-95.as13285.net (78.144.11.95)  16.140 ms host-78-144-11-119.as13285.net (78.144.11.119)  16.551 ms host-78-144-11-95.as13285.net (78.144.11.95)  16.463 ms
 6  * * *
 7  * * *
 8  * * *
 9  * * *
10  * * *
...

Traffic stops at this host: 195.66.225.179 which is probably a firewall and is blocking the traffic.

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6
  • That is not my domain name. That is the service which checks port forwarding.
    – Amresh Singh
    Jul 9, 2014 at 11:33
  • Yes, it is your domain name: dig yougetsignal.com returns yougetsignal.com. 300 IN A 141.101.117.86 (as well as 141.101.116.86).
    – MadHatter
    Jul 9, 2014 at 11:41
  • @MadHatter I think AmreshSingh was using this website to check his own. If you visit the website it has a series of network tools on it.
    – Matthew Ife
    Jul 9, 2014 at 11:42
  • Oh, blast. Yes, I can see how his first sentence can be read that way as well. That stuffs most of my analysis above, too.
    – MadHatter
    Jul 9, 2014 at 11:43
  • English is not my first language so .. Oops
    – Amresh Singh
    Jul 9, 2014 at 11:52
1

So, given the real IP address here is the traceroute; Note the routing appears to change regularly, but these two examples appear to take similar paths.

Port 80

traceroute to 103.231.8.238 (103.231.8.238), 30 hops max, 60 byte packets
 1  192.168.1.1  0.290 ms  0.435 ms  0.520 ms
 2  92.25.242.1  13.350 ms  13.348 ms  13.343 ms
 3  78.151.225.189  15.084 ms  15.086 ms  15.099 ms
 4  78.151.225.200  15.236 ms  15.873 ms 78.151.225.184  15.907 ms
 5  78.144.11.123  16.353 ms 78.144.11.121  16.227 ms 78.144.11.135  16.243 ms
 6  195.66.224.209  18.715 ms 78.144.11.2  16.502 ms 78.144.10.252  16.443 ms
 7  206.126.236.88  96.076 ms  93.854 ms 145.253.33.238  14.138 ms
 8  182.19.105.75  132.438 ms 182.19.105.73  131.902 ms  131.863 ms
 9  * * *
10  103.1.112.13  140.948 ms 182.19.115.224  278.477 ms  278.436 ms
11  103.13.96.170  154.360 ms  153.584 ms 182.19.115.226  275.564 ms
12  103.241.180.132  137.192 ms  138.187 ms 182.19.115.100  276.826 ms
13  103.231.8.238  138.987 ms  138.867 ms  140.010 ms

And port 3306:

 1  192.168.1.1  0.380 ms  0.468 ms  0.574 ms
 2  92.25.242.1  13.358 ms  13.366 ms  13.399 ms
 3  78.151.225.189  14.904 ms  14.904 ms  14.931 ms
 4  78.151.225.156  15.081 ms  15.676 ms 78.151.225.188  32.598 ms
 5  78.144.11.111  16.741 ms 78.144.11.119  19.341 ms 78.144.11.125  16.725 ms
 6  78.144.11.6  16.818 ms 78.144.10.254  17.168 ms 78.144.11.6  17.104 ms
 7  206.126.236.88  96.258 ms 145.253.33.238  14.267 ms 206.126.236.88  94.096 ms
 8  63.218.162.165  344.874 ms 182.19.105.75  132.858 ms 63.218.162.165  344.861 ms
 9  63.218.163.170  284.351 ms 123.63.182.125  138.510 ms 63.218.163.170  283.633 ms
10  103.1.112.13  138.879 ms  140.004 ms 182.19.115.224  277.669 ms
11  103.13.96.170  154.360 ms 182.19.107.1  275.934 ms 103.13.96.170  152.461 ms
12  103.241.180.132  136.943 ms  138.046 ms 182.19.115.100  275.782 ms
13  182.19.105.75  274.382 ms  274.097 ms *
14  123.63.182.125  280.577 ms *  281.215 ms
15  * 103.1.112.13  281.433 ms *
16  103.13.96.170  297.287 ms *  296.211 ms
17  * * *
18  * * *
19  * * *
...

Of interest is hops 12 to 13. On the port 80 example the 13th hop is your server. On port 3306 the 13th hop is a 182.19.105.75 address, this also comes up in other traceroutes as being the next to last hop from the destionation. I assume that there is some DNAT happening which is redirecting the traffic back out from this network to a different destination, its not possible to tell what this destination might be from the output though.

Some traceroutes show some signs of looping though, such as this..

 8  182.19.105.75  148.637 ms  133.271 ms 63.218.162.165  345.590 ms
 9  * * 123.63.182.125  137.830 ms
10  103.1.112.13  140.637 ms *  140.108 ms
11  182.19.107.1  275.851 ms 103.13.96.170  153.820 ms 182.19.107.1  275.465 ms
12  103.241.180.132  136.681 ms 182.19.115.100  275.113 ms 103.241.180.132  136.907 ms
13  182.19.105.75  274.357 ms  274.330 ms  274.211 ms
14  123.63.182.125  282.631 ms  282.339 ms *
15  * 103.1.112.13  283.497 ms  282.053 ms
16  * * 103.13.96.170  298.444 ms
17  103.241.180.132  279.360 ms * *

I never end up getting a TTL exceeded message however.

Check what you have setup in your router and port forwarding, something appears to be incorrectly configured.

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