juanfont/headscale · error

alias not supported for SSH source

Error message

alias not supported for SSH source

What it means

Returned by SSHSrcAliases.UnmarshalJSON (hscontrol/policy/v2/types.go:2916) when an element of an SSH rule's src array decodes to an alias type other than *Username, *Group, *Tag, or *AutoGroup. SSH sources describe tailnet identities, so IP/CIDR literals and host aliases are structurally rejected at parse time.

Source

Thrown at hscontrol/policy/v2/types.go:143

	ErrGroupValueNotArray          = errors.New("group value must be an array of users")
	ErrInvalidHostIP               = errors.New("hostname contains invalid IP address")
	ErrTagNotDefined               = errors.New("tag not found")
	ErrAutoApproverNotAlias        = errors.New("auto approver is not an alias")
	ErrInvalidACLAction            = errors.New("invalid ACL action")
	ErrInvalidSSHAction            = errors.New("invalid SSH action")
	ErrInvalidProtocolNumber       = errors.New("invalid protocol number")
	ErrProtocolLeadingZero         = errors.New("leading 0 not permitted in protocol number")
	ErrProtocolOutOfRange          = errors.New("protocol number out of range (0-255)")
	ErrAutogroupNotSupported       = errors.New("autogroup not supported in headscale")
	ErrAutogroupInternetSrc        = errors.New("autogroup:internet can only be used in ACL destinations")
	ErrAutogroupSelfSrc            = errors.New("\"autogroup:self\" not valid on the src side of a rule")
	ErrAutogroupNotSupportedACLSrc = errors.New("autogroup not supported for ACL sources")
	ErrAutogroupNotSupportedACLDst = errors.New("autogroup not supported for ACL destinations")
	ErrAutogroupDangerAllDst       = errors.New("cannot use autogroup:danger-all as a dst")
	ErrAutogroupNotSupportedSSHSrc = errors.New("autogroup not supported for SSH sources")
	ErrAutogroupNotSupportedSSHDst = errors.New("autogroup not supported for SSH destinations")
	ErrHostNotDefined              = errors.New("host not defined in policy")
	ErrSSHSourceAliasNotSupported  = errors.New("alias not supported for SSH source")
	ErrSSHDestAliasNotSupported    = errors.New("alias not supported for SSH destination")
	ErrUnknownField                = errors.New("unknown field")
	ErrProtocolNoSpecificPorts     = errors.New("protocol does not support specific ports")
	ErrTestEmptyAssertions         = errors.New("test entry must have at least one of \"accept\" or \"deny\"")
	ErrTestProtocolNotAllowed      = errors.New("test protocol must be tcp, udp, sctp, or empty")
	ErrTestDestinationMultiPort    = errors.New("test destination port must be a single port")
	ErrTestDestinationCIDR         = errors.New("test destination must be a single host, not a CIDR range")
	ErrAutogroupInternetTestDst    = errors.New("autogroup:internet not valid as a test destination")
	ErrSSHTestEmptySrc             = errors.New("SSH tests entry must have a non-empty src")
	ErrSSHTestEmptyDst             = errors.New("SSH tests entry must have at least one dst")
	ErrSSHTestDstUnknownTag        = errors.New("SSH tests dst contains unknown tag")
	ErrSSHTestDstDisallowedElement = errors.New("SSH tests dst contains disallowed element")
)

type resolved struct {
	ips netipx.IPSet
}

View on GitHub (pinned to 565fd254d0)

Solutions

1. Express SSH src as a user ("alice@example.com"), group ("group:admin"), tag, or autogroup:member/tagged
2. If IP-based restriction is the goal, constrain at the ACL layer instead — SSH rules cannot filter by address
3. Check for stray quotes/typos that make an entry parse as an unexpected type

Example fix

// before
"ssh": [{"action": "accept", "src": ["100.64.0.1"], "dst": ["tag:server"], "users": ["root"]}]

// after
"ssh": [{"action": "accept", "src": ["group:admin"], "dst": ["tag:server"], "users": ["root"]}]

func validSSHSrc(s string) bool {
	return strings.HasPrefix(s, "autogroup:") || strings.HasPrefix(s, "tag:") ||
		strings.HasPrefix(s, "group:") || strings.Contains(s, "@")
}

func isSSHSourceAliasNotSupported(err error) bool {
	return errors.Is(err, policy.ErrSSHSourceAliasNotSupported)
}

if err := json.Unmarshal(b, &p); err != nil {
	if errors.Is(err, policy.ErrSSHSourceAliasNotSupported) {
		return fmt.Errorf("SSH src must be user/group/tag/autogroup (no IPs or hosts): %w", err)
	}
	return err
}

When it happens

Trigger: An SSH rule like {"src": ["100.64.0.1"], ...} or {"src": ["10.0.0.0/8"], ...} — raw addresses/prefixes decode to IP alias types and fail the switch. The error includes the Go type that was rejected (%T).

Common situations: Trying to SSH-allow by IP address (common instinct from sshd AllowUsers/Match Address); pasting an ACL src line that uses hosts or CIDRs into an ssh rule.

Related errors

• alias not supported for SSH destination
• tags in SSH source cannot access user-owned devices
• user destination requires source to contain only that same u
• autogroup:self destination requires source to contain only u
• tags in SSH source cannot access autogroup:member (user-owne

AI-assisted analysis of juanfont/headscale@565fd254d0 (2026-08-15). Data as JSON: /api/errors/959a4cdb1d1096f1. Report an issue: GitHub.