- Plesk for Linux
1. Domain example.com shows Plesk Default Page.
2. Domain is assigned to a floating IP in DigitalOcean.
3. With tcpdump utility it is shown that domain's traffic goes to an internal IP:
# tcpdump -n "dst port 80 and src host 203.0.113.2"
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
05:22:50.870868 IP 203.0.113.2.57486 > 192.0.2.2.http: Flags [F.], seq 1635309888, ack 2130394795, win 16425, length 0
05:22:50.876045 IP 203.0.113.2.57487 > 192.0.2.2.http: Flags [F.], seq 915298234, ack 1165555098, win 16425, length 0
05:22:50.876267 IP 203.0.113.2.57488 > 192.0.2.2.http: Flags [F.], seq 61561314, ack 203860145, win 16425, length 0
05:22:50.881429 IP 203.0.113.2.57473 > 192.0.2.2.http: Flags [F.], seq 2525189352, ack 2262210741, win 16425, length 0
05:22:50.882324 IP 203.0.113.2.57496 > 192.0.2.2.http: Flags [S], seq 563497673, win 8192, options [mss 1460,nop,wscale 2,nop,nop,sackOK], length 0
05:22:50.882627 IP 203.0.113.2.57491 > 192.0.2.2.http: Flags [S], seq 733373586, win 8192, options [mss 1460,nop,wscale 2,nop,nop,sackOK], length 0
05:22:50.883245 IP 203.0.113.2.57485 > 192.0.2.2.http: Flags [F.], seq 2990225291, ack 1966219984, win 16425, length 0
where 203.0.113.2 - IP address of a machine the website is requested from.
4. External IP address shown with a dig command:
# dig +short example.com
5. External IP is configured for the website at Domains > example.com > Web Hosting Access in Plesk.
Incorrect IP address mapping in Plesk. In the DigitalOcean documentation it is written:
Network traffic between a Floating IP and a Droplet flows through an anchor IP, which is an IP address that is aliased to a Droplet's public network interface (
eth0). As such, a Droplet must have an anchor IP before a Floating IP can be assigned to it.
Despite of the DigitalOcean system that maps IP addresses, IP addresses should be mapped in Plesk as well.
1. Add floating IP address as public IP to the anchor at Plesk > Tools & Settings > IP Addresses > 192.0.2.2 > Public IP address - 203.0.113.3.
2. Make sure that 192.0.2.2 IP address is selected for the website at Domains > example.com > Web Hosting Access.