Hello all. I’m trying to change the SSH port on an Oracle VM, but I’m getting nowhere and I don’t know where to solve the issue.

I have changed the SSH port:

edit /etc/ssh/sshd_config

Entered the port info:

Port 5522

I restarted the service:

sudo systemctl restart ssh

And made sure that the port is open:

ss -an | grep 5522
tcp   LISTEN 0      128                                                                               0.0.0.0:5522                0.0.0.0:*            
tcp   LISTEN 0      128                                                                                  [::]:5522                   [::]:*    

---

I also allow incoming traffic to 5522:

sudo ufw allow 22/tcp comment 'Open port ssh tcp port 22'

AND just to make sure, I allow ‘routed’:

sudo ufw default allow FORWARD

And make sure the FW config is valid:

sudo ufw status verbose
Status: active
Logging: on (medium)
Default: deny (incoming), allow (outgoing), allow (routed)
New profiles: skip

To                         Action      From
--                         ------      ----
22/tcp                     ALLOW IN    Anywhere                   # Open port ssh tcp port 22
5522/tcp                   ALLOW IN    Anywhere                  
22/tcp (v6)                ALLOW IN    Anywhere (v6)              # Open port ssh tcp port 22
5522/tcp (v6)              ALLOW IN    Anywhere (v6)              # Open real ssh tcp port 22

Yet, I cannot connect to this server. Trying to ssh -vvvv -p 5522 [ip-adress] yields this:

OpenSSH_9.0p1 Ubuntu-1ubuntu8.4, OpenSSL 3.0.8 7 Feb 2023
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: include /etc/ssh/ssh_config.d/*.conf matched no files
debug1: /etc/ssh/ssh_config line 21: Applying options for *
debug2: resolve_canonicalize: hostname 129.x.x.5 is address
debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts' -> '/home/x/.ssh/known_hosts'
debug3: expanded UserKnownHostsFile '~/.ssh/known_hosts2' -> '/home/x/.ssh/known_hosts2'
debug3: ssh_connect_direct: entering
debug1: Connecting to 129.x.x.5 [129.x.x.5] port 5522.
debug3: set_sock_tos: set socket 3 IP_TOS 0x10
debug1: connect to address 129.x.x.5 port 5522: No route to host
ssh: connect to host 129.x.x.5 port 5522: No route to host

I can connect just fine when the port is at 22, but as soon as I change it to 5522, i get the ‘no route to host’ error.

I’ve made sure I have rules on Oracle cloud that allows ingress and egress traffic to 0.0.0.0/24 on all protocols, no matter the destination / source.

What am I doing wrong? It feels that this problem is host (server) based rather client based, since I’m getting a routing error. Do I need to configure the routing for that port specifically, and if so how?

PS: Also, connecting to localhost:5522 from the server itself works fine. So the problem is not in the configuration, but likely network related.