diff --git a/components/app.js b/components/app.js
index 094a5f5..856206f 100644
--- a/components/app.js
+++ b/components/app.js
@@ -8,12 +8,13 @@ import ConnectForm from "./connect-form.js";
 import JoinForm from "./join-form.js";
 import Help from "./help.js";
 import NetworkForm from "./network-form.js";
+import AuthForm from "./auth-form.js";
 import Composer from "./composer.js";
 import ScrollManager from "./scroll-manager.js";
 import Dialog from "./dialog.js";
 import { html, Component, createRef } from "../lib/index.js";
 import { strip as stripANSI } from "../lib/ansi.js";
-import { SERVER_BUFFER, BufferType, ReceiptType, ServerStatus, Unread, State } from "../state.js";
+import { SERVER_BUFFER, BufferType, ReceiptType, ServerStatus, Unread, State, getServerName } from "../state.js";
 import commands from "../commands.js";
 import { setup as setupKeybindings } from "../keybindings.js";
 import * as store from "../store.js";
@@ -191,6 +192,7 @@ export default class App extends Component {
 		this.handleNetworkSubmit = this.handleNetworkSubmit.bind(this);
 		this.handleNetworkRemove = this.handleNetworkRemove.bind(this);
 		this.handleDismissError = this.handleDismissError.bind(this);
+		this.handleAuthSubmit = this.handleAuthSubmit.bind(this);
 
 		this.saveReceipts = debounce(this.saveReceipts.bind(this), 500);
 
@@ -1377,6 +1379,35 @@ export default class App extends Component {
 		this.setState({ dialog: null, dialogData: null });
 	}
 
+	handleAuthClick(serverID) {
+		let client = this.clients.get(serverID);
+		this.openDialog("auth", { username: client.nick });
+	}
+
+	handleAuthSubmit(username, password) {
+		let serverID = State.getActiveServerID(this.state);
+		let client = this.clients.get(serverID);
+		client.authenticate("PLAIN", { username, password }).then(() => {
+			let firstClient = this.clients.values().next().value;
+			if (client !== firstClient) {
+				return;
+			}
+
+			let autoconnect = store.autoconnect.load();
+			if (!autoconnect) {
+				return;
+			}
+
+			console.log("Saving SASL PLAIN credentials");
+			autoconnect = {
+				...autoconnect,
+				saslPlain: { username, password },
+			};
+			store.autoconnect.put(autoconnect);
+		});
+		this.dismissDialog();
+	}
+
 	handleAddNetworkClick() {
 		this.openDialog("network");
 	}
@@ -1560,6 +1591,13 @@ export default class App extends Component {
 				</>
 			`;
 			break;
+		case "auth":
+			dialog = html`
+				<${Dialog} title="Login to ${getServerName(activeServer, activeBouncerNetwork, isBouncer)}" onDismiss=${this.dismissDialog}>
+					<${AuthForm} username=${dialogData.username} onSubmit=${this.handleAuthSubmit}/>
+				</>
+			`;
+			break;
 		}
 
 		let error = null;
@@ -1616,7 +1654,9 @@ export default class App extends Component {
 						server=${activeServer}
 						isBouncer=${isBouncer}
 						onChannelClick=${this.handleChannelClick}
-						onNickClick=${this.handleNickClick}/>
+						onNickClick=${this.handleNickClick}
+						onAuthClick=${() => this.handleAuthClick(activeBuffer.server)}
+					/>
 				</section>
 			</>
 			${memberList}
diff --git a/components/auth-form.js b/components/auth-form.js
new file mode 100644
index 0000000..6eccdaa
--- /dev/null
+++ b/components/auth-form.js
@@ -0,0 +1,51 @@
+import { html, Component } from "../lib/index.js";
+
+export default class NetworkForm extends Component {
+	state = {
+		username: "",
+		password: "",
+	};
+
+	constructor(props) {
+		super(props);
+
+		this.handleChange = this.handleChange.bind(this);
+		this.handleSubmit = this.handleSubmit.bind(this);
+
+		if (props.username) {
+			this.state.username = props.username;
+		}
+	}
+
+	handleChange(event) {
+		let target = event.target;
+		let value = target.type == "checkbox" ? target.checked : target.value;
+		this.setState({ [target.name]: value });
+	}
+
+	handleSubmit(event) {
+		event.preventDefault();
+
+		this.props.onSubmit(this.state.username, this.state.password);
+	}
+
+	render() {
+		return html`
+			<form onChange=${this.handleChange} onSubmit=${this.handleSubmit}>
+				<label>
+					Username:<br/>
+					<input type="username" name="username" value=${this.state.username} required/>
+				</label>
+				<br/><br/>
+
+				<label>
+					Password:<br/>
+					<input type="password" name="password" value=${this.state.password} required autofocus/>
+				</label>
+				<br/><br/>
+
+				<button>Login</button>
+			</form>
+		`;
+	}
+}
diff --git a/components/buffer.js b/components/buffer.js
index e661a1b..8f2e30e 100644
--- a/components/buffer.js
+++ b/components/buffer.js
@@ -2,7 +2,7 @@ import { html, Component } from "../lib/index.js";
 import linkify from "../lib/linkify.js";
 import * as irc from "../lib/irc.js";
 import { strip as stripANSI } from "../lib/ansi.js";
-import { BufferType, getNickURL, getChannelURL, getMessageURL } from "../state.js";
+import { BufferType, ServerStatus, getNickURL, getChannelURL, getMessageURL } from "../state.js";
 import * as store from "../store.js";
 import Membership from "./membership.js";
 
@@ -457,6 +457,26 @@ class ProtocolHandlerNagger extends Component {
 	}
 }
 
+function AuthNagger({ server, onClick }) {
+	let accDesc = "an account on this server";
+	if (server.isupport.has("NETWORK")) {
+		accDesc = "a " + server.isupport.get("NETWORK") + " account";
+	}
+
+	function handleClick(event) {
+		event.preventDefault();
+		onClick();
+	}
+
+	return html`
+		<div class="logline">
+			<${Timestamp}/>
+			${" "}
+			You are unauthenticated on this server, <a href="#" onClick=${handleClick}>login</a> if you have ${accDesc}
+		</div>
+	`;
+}
+
 class DateSeparator extends Component {
 	constructor(props) {
 		super(props);
@@ -508,6 +528,9 @@ export default class Buffer extends Component {
 			let name = server.isupport.get("NETWORK");
 			children.push(html`<${ProtocolHandlerNagger} bouncerName=${name}/>`);
 		}
+		if (buf.type == BufferType.SERVER && server.status == ServerStatus.REGISTERED && server.supportsSASLPlain && !server.account) {
+			children.push(html`<${AuthNagger} server=${server} onClick=${this.props.onAuthClick}/>`);
+		}
 
 		let onChannelClick = this.props.onChannelClick;
 		let onNickClick = this.props.onNickClick;
diff --git a/state.js b/state.js
index e8fa354..33b3142 100644
--- a/state.js
+++ b/state.js
@@ -256,6 +256,7 @@ export const State = {
 			isupport: new Map(),
 			users: new irc.CaseMapMap(null, irc.CaseMapping.RFC1459),
 			account: null,
+			supportsSASLPlain: false,
 		});
 		return [id, { servers }];
 	},
@@ -346,6 +347,8 @@ export const State = {
 					};
 				}),
 			};
+		case "CAP":
+			return updateServer({ supportsSASLPlain: client.supportsSASL("PLAIN") });
 		case irc.RPL_LOGGEDIN:
 			return updateServer({ account: msg.params[2] });
 		case irc.RPL_LOGGEDOUT: