Port 22128 GSIDCAP
Port 22128 is the IANA-assigned gsidcap port for GSI dCache Access Protocol (TCP).
What is port 22128 used for?
Port 22128 is assigned to gsidcap and uses TCP. The IANA registry describes the service as “GSI dCache Access Protocol”. It sits above the registered range, where most numbers are transient client ports. A fixed high port is worth documenting precisely because tooling often assumes the default.
Ports are the transport-layer address a service listens on. A client that wants to reach gsidcap connects to port 22128. If nothing is listening, the connection is refused. That is why a port conflict appears whenever two processes try to bind the same number.
Use the commands below to confirm whether port 22128 is actually in use before you change firewall rules. Blocking the port stops new inbound traffic at the firewall, but it does not stop a local process from listening, and it does not remove the service from the machine.
Browse all Caching and in-memory stores ports
Source: IANA Service Name and Transport Protocol Port Number Registry. Registered assignee: [Christoph_Anton_Mitt].
Check and block port 22128
Copy-ready commands for the protocols assigned to this port. Run the check first, then block only what should not be reachable.
Check on Linux
sudo ss -tlpn 'sport = :22128'Check on Windows
Get-NetTCPConnection -LocalPort 22128 -State Listen -ErrorAction SilentlyContinueBlock with UFW
sudo ufw deny 22128/tcpBlock with iptables
sudo iptables -A INPUT -p tcp --dport 22128 -j DROPThese commands are examples for a typical host. Check the listener before you change firewall rules, and persist iptables rules with iptables-save or netfilter-persistent. On Windows, use Windows Defender Firewall or New-NetFirewallRule for persistent blocks. The iptables rules here cover IPv4; mirror them with ip6tables if IPv6 is enabled.
Is port 22128 safe to expose?
This port is not on our curated list of services with a widely exploited profile. Exposure is only safe when the listening service is intended, patched and protected by a firewall. Keep the listening service patched and remove it if unused. A default-deny firewall policy with explicit allow rules is still the safest baseline.
Where port 22128 is usually used
Most traffic on port 22128 falls into these scenarios. The demo below is a safe way to confirm the listener before you change anything.
- Session storage, rate limiting and hot-key caching in front of a slower database.
- Several application instances sharing counters or job state on port 22128.
- Local development stacks that run the cache in a container.
Ping the cache
Confirm the listener is reachable before you debug client configuration or authentication.
nc -vz 127.0.0.1 22128Common problems with port 22128
Connection refused or timed out
Refused usually means the host is reachable but nothing is listening on port 22128. A timeout more often means a firewall drop, a wrong host or a service bound to a different interface.
Port already in use
Find the process holding the port with sudo ss -tlpn 'sport = :22128' or sudo lsof -i :22128. Stop that process or configure it to bind another port; killing it without identifying it can take down a production service.
Firewall rule did not survive a reboot
UFW and Windows Firewall keep rules across restarts. Raw iptables rules do not: save them with iptables-save or the netfilter-persistent package, and re-apply after upgrades that reset the ruleset.
The port is blocked but still reachable
A firewall rule filters inbound traffic; it does not close the listener. Confirm with the check command above and bind the service to 127.0.0.1 when only local clients need it.
Port 22128 at a glance
| Port number | 22128 |
|---|---|
| Service name | gsidcap |
| Transport protocol | TCP |
| Category | Caching and in-memory stores |
| Range | High port (10001–65535) |
| Risk level | Standard/Low |
| Registered assignee | [Christoph_Anton_Mitt] |
| Registry description | GSI dCache Access Protocol |
| Source | IANA Service Name and Transport Protocol Port Number Registry |
Frequently asked questions
What is port 22128 used for?
Port 22128 (GSIDCAP) uses TCP. GSI dCache Access Protocol.
How do I check if port 22128 is open?
On Linux run `sudo ss -tlpn 'sport = :22128'`. On Windows run `Get-NetTCPConnection -LocalPort 22128 -State Listen -ErrorAction SilentlyContinue` in PowerShell. If the port is open, the output shows a process listening on port 22128; empty output usually means nothing is bound to it.
How do I block port 22128?
With UFW run `sudo ufw deny 22128/tcp`. With iptables run `sudo iptables -A INPUT -p tcp --dport 22128 -j DROP`. Persist the iptables rules with your distribution's netfilter-persistent or iptables-save tooling so they survive a reboot.
Is port 22128 safe to expose?
This port is not on our curated list of services with a widely exploited profile. Exposure is only safe when the listening service is intended, patched and protected by a firewall. Nevertheless, keep the listening service patched and remove it if unused. A default-deny firewall policy with explicit allow rules is still the safest baseline.
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Primary data: IANA Service Name and Transport Protocol Port Number Registry.
Last reviewed 2026-10-30 · Methodology · About · Privacy