3 Ways to check IP encapsulation in Linux

The website is not open, SSH is not connected, this is a lot of webmaster pain. The following example 3 ways to determine if the IP is blocked.

1, routing Analysis method

# traceroute 212.239.8.22//linux down
Traceroute to 212.239.8.22 (212.239.8.22), hops max, byte packets
1 192.168.10.1 (192.168.10.1) 0.308 ms 0.515 ms 0.634 ms
2 * * *
3 124.74.57.93 (124.74.57.93) 5.325 ms 5.314 ms 5.310 ms
4 101.95.42.177 (101.95.42.177) 5.219 ms 5.222 ms 5.214 ms
5 61.152.86.178 (61.152.86.178) 6.495 ms 6.604 ms 6.596 ms
6 * * *
7 * * *
8 * * *
9 * * *
10 * * *

F:\test> tracert 212.239.8.22//windows under

In the IP query tool check, you will find that 61.152.86.178 is the backbone of Shanghai Telecom, here is not a pass. I can only say it's blocked off.
2, login wall outside vps,ping 212.239.8.22, this method premise is you have two outside the wall VPs, and not be sealed at the same time. If the ping outside the wall, the wall of the ping impassability, the explanation was blocked.
3, if the use of VPN or proxy can access, do not just can't access, the description by the wall.

Add: L

First view the current rule:

Iptables--list

[Root@joytest1 ~]# iptables--list
Chain INPUT (Policy ACCEPT)
Target Prot opt source destination
ACCEPT All--xxxx.xxxx.50.45 anywhere
ACCEPT All--anywhere anywhere state related,established
ACCEPT All-anywhere anywhere
ACCEPT TCP--Anywhere anywhere state NEW TCP DPT:SSH
ACCEPT ICMP--anywhere anywhere
ACCEPT TCP--anywhere anywhere TCP DPT:SVN
ACCEPT TCP--anywhere anywhere TCP DPT:PPTP
ACCEPT GRE-Anywhere anywhere
ACCEPT UDP--anywhere anywhere UDP Dpt:domain
DROP All-anywhere anywhere
ACCEPT TCP--anywhere anywhere TCP dpt:ni-ftp

Increase:

Iptables-a input-s xxx.xx.xxx.xxx-j ACCEPT

Restart Service

Service Iptables Restart