check connectivity of server

How-to-use-glorytun-with-2-isp-(draft).md

@@ -27,7 +27,35 @@ We be use pre-compiled version of glorytun 0.2.2, for client and server, all com
 
 ## **Server side:**
 
-download glorytun binare file
+First we need check interfaces and connectivity, try this command  `ip a`
+
+> 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
+
+> 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
+
+>    inet 195.245.103.245/24 brd 195.245.103.255 scope global eth0
+
+
+we see lo is a local interface and nic interface eth0 with ip address 195.245.103.245 and state is UP
+
+next, test connectivity with this command: `ping 8.8.4.4 -c4`
+> PING 8.8.4.4 (8.8.4.4) 56(84) bytes of data.
+
+> 64 bytes from 8.8.4.4: icmp_seq=1 ttl=46 time=17.8 ms
+
+> 64 bytes from 8.8.4.4: icmp_seq=2 ttl=46 time=18.0 ms
+
+> 64 bytes from 8.8.4.4: icmp_seq=3 ttl=46 time=17.9 ms
+
+> 64 bytes from 8.8.4.4: icmp_seq=4 ttl=46 time=17.9 ms
+
+> --- 8.8.4.4 ping statistics ---
+
+> 4 packets transmitted, 4 received, 0% packet loss, time 3004ms
+
+> rtt min/avg/max/mdev = 17.842/17.924/18.000/0.173 ms
+
+all work and ready, now download glorytun binare file
 
 `wget https://github.com/angt/glorytun/releases/download/v0.2.2/glorytun-0.2.2-x86_64-linux-musl.bin`