To test the reachability of our servers, you can use the ping utility. Example of a successfully established ping connection:

roman@braiins ~ % ping eu.stratum.slushpool.com
PING eu.stratum.slushpool.com (46.101.236.153): 56 data bytes
64 bytes from 46.101.236.153: icmp_seq=0 ttl=52 time=29.191 ms
64 bytes from 46.101.236.153: icmp_seq=1 ttl=52 time=59.535 ms
64 bytes from 46.101.236.153: icmp_seq=2 ttl=52 time=21.847 ms
64 bytes from 46.101.236.153: icmp_seq=3 ttl=52 time=56.541 ms
64 bytes from 46.101.236.153: icmp_seq=4 ttl=52 time=28.268 ms

--- eu.stratum.slushpool.com ping statistics ---
5 packets transmitted, 5 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 21.847/39.076/59.535/15.716 ms

If for some reason the ping utility is not available, you can also use Telnet instead. Example of a successfully established Telnet connection:

telnet stratum.slushpool.com 3333
Trying 34.248.17.246...
Connected to stratum.slushpool.com.