SSH: Did not receive identification string from x.x.x.x

Forum|Forum|18 days ago
July 19, 2026
5 replies
51 views

Hi,

I got this error when trying to SSH from a specific server:

sshd -1 output shows,

“This ip x.x.x.x is not blocked

fd 7 is not O_NONBLOCK

…

Did not receive identification string from x.x.x.x”

Any KBs related to this?

Thank you!

FortiGate

AEK

SuperUser

Hi

Do you mean you are trying to ssh from a server to FGT, or from a server to another server behind FGT?

AEK

heyyoAuthor

Explorer III

SSH from a server to FGT itself. Firewall is in HA with ha-mgmt-status enabled and the configured management interface already has ssh allowed. I noticed that iprope debug shows firewall accept the traffic in the root vdom, but is dropped by policy-4294967295 in vd-vsys_hamgmt vdom

Toshi_Esumi

SuperUser

There was a post 3 years ago, which showed up in my Google search at the top.

Toshi

AEK

SuperUser

Also policy-4294967295 is a local in policy.
Command “show firewall local-in” should help you find if any local-in policy is denying the ssh traffic to your FGT.

AEK

D

davidwarner122

Visitor III

This log usually indicates the client didn't complete the SSH handshake, not that the IP is blocked. Check the client with ssh -vvv, verify any firewall or proxy in the path, and review the server logs at the same time for more details.

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