IP Messenger Help

2026/08/16 H.Shirouzu & FastCopy Lab, LLC.

Index

IP Messenger Pro has been released!

1. Overview
2. License/Environment/Install
3. Usage/Screen description
- Screen Shot/Capture
- LogViewer
4. Settings
- Member Master Settings
- RecvTrans (Slack or etc)
- Auto Update
5. Ports/Registry
6. Troubleshooting
7. CommandLine
8. Support
9. Tips/Shortcut
10. History

1. Overview

IP Messenger is a pop up style LAN message communication software for multi platforms. It is based on TCP and UDP/IP.

Members on the LAN are detected dynamically. This software does not require a server machine.
Simple, lightweight, and free software :-)

1. Powerful LogViewer (ver4.0 or later)
2. Folder/file transfer
3. Embedded images in a message
4. RSA(2048bit) + AES(256bit) + SHA-256 for secure communication
5. IPv6 Multicast support
6. Over routers (Member Master function. v4.5 or later)

2. License/Environment/Install

IP Messenger ver5.x License

Copyright 1996-2026 SHIROUZU Hiroaki All rights reserved.
Copyright 2015-2018 Asahi Net, Inc. All rights reserved.
Copyright 2018-2026 FastCopy Lab, LLC. All rights reserved.

Redistributing and using this software, commercial or non-commercial, is permitted if the following conditions are met:

1. Redistributions of this software must retain the above copyright notice, this list of conditions and the following disclaimer.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Requirements

Windows 7/8/8.1/10/11 (and Server2008/2012/2016/2019/2022/2025)

Install/Uninstall

To install, run ipmsg5xx_installer.exe.
(/h shows the available options such as /silent and /extract)
To uninstall, run "Uninstall IPMSG" in the "IP Messenger for Win" folder in the Start Menu.
(Or it can be done from Windows Settings "Apps and Features")

3. Usage/Screen description

Task tray icon

A single (or double) left-click on the icon opens the Send Message window.
Right single click on the icon opens IPMsg menu such as Settings, Absence Mode, View Log, Help, etc.

Send Message Window

Send
Select recipients and press the Send button to send a message.
Hovering over the Send button shows the current recipient list.
(If [Seal] is checked, the message is sent sealed, with an open button)

To transfer File/Folder, Drag & Drop File/Folder to Send Window. (or select "File/Folder Attach" from the right-click menu)

(File/Folder transfer does not start until the receiver starts to download it. An automatic-receive mode, configured on the receiver side, is also available since v3.5.
If the sender restarts IPMSG, the download permission info is cleared, so files attached before the restart can no longer be downloaded.)

Prefix color of the user list
Indicates the features supported by each user.

color	meaning
white	Embedded images, attached files, RSA2048/AES256/SHA-256(orSHA-1) encryption/sign
light pink	Same as white except disabling embedded images
light gray	Attached files, RSA encryption
light blue	Attached files, no encryption
dark gray	Basic message communication

Attention: ! mark indicates absence mode

The order of Send Message window header item list can be changed by Drag & Drop. Right click and select "Size/Font/Pos Setting" → "Save size/header as default" to save the order and widths.

Right click on the window and select from the menu: Priority Settings, Group Select, Search User (Ctrl-[F]), Font Setting, Size Saving, Fix Position, Disp Setting.

Sort/Filter display order priority Users are sorted in ascending order of priority value.
Users with the same priority are sorted according to "Disp Setting..." → "Broad-level User Sort Settings"

Screen Shot/Capture

Click the camera button at the bottom-left of the Send window to start capture.
An area-selected desktop image can be annotated with markers, pasted into the Send Message Window, and saved as a PNG/JPG/BMP/GIF/TIFF file.
When capture starts, the source Send Message Window is minimized by default (this can be changed in settings; holding Shift when starting capture inverts the behavior).

In capture mode, you can draw/edit "pen, straight line, rectangle, arrow with comment, mask, range move," etc.
(Useful as a simple screen capture tool.)

- Pressing Shift + Ctrl during capture-start / area-selection snaps the capture range to the size of the window under the mouse cursor.
- Holding Shift while moving the mouse with "pen" etc. moves (translates) the shape being drawn.
- Holding Ctrl while drawing a "straight line" locks it to horizontal or vertical.

To embed clipboard image, press Ctrl-[V] in the edit box or use the right-click menu. (Max. 10 images)
If logging setting is enabled, send/receive images are saved in ipmsg_img sub-folder of logfile folder.
(Because embedded images are sent/received via the IPMsg file-transfer mechanism, TCP port 2425 must be open)
Right-click an embedded image and select "Save Selected Image..." to save it to a file.

Receive Message Window

Right click on the window and select from the menu: Font Setting, Size Setting, Fix Position.

If you receive a message with an attachment, then an attachment button will be displayed. Folder transfers are always saved as a new folder; an existing folder can't be overwritten.

Strength	PublicKey	CommonKey	Signature	Receive Window Title	Log File
Strongest	RSA 2048bit	AES 256bit	RSA+SHA-256	Receive Message ++++	(RSA2/Signed+)
Strong	RSA 2048bit	AES 256bit	RSA+SHA-1	Receive Message +++	(RSA2/Signed)
Strong	RSA 2048bit	AES 256bit	Nothing	Receive Message ++	(RSA2)
Weak	RSA 1024bit	Blowfish 128bit	Nothing	Receive Message +	(RSA)
Nothing	Nothing	Nothing	Nothing	Receive Message

The strongest mode supported by both sender and receiver is used.
UserID is extended with fingerprint in v3.0 or later. ("uid" → "uid-<finger_print_hexstr>")
This prevents impersonation and improves user uniqueness.
If a user forges a fingerprint-suffixed UserID (without owning the public key of that fingerprint) and sends a message, "(Impersonate?)" is shown in the receive window title.

LogViewer

Powerful Viewer that can show message log with embedded images

Main Features

It can display and search tens of thousands of messages with embedded images at high speed

It can narrow messages for specified user by 1 click

It has "Marker", "Favorite", "Comment" functions.

(and also has "Self memo", "Embedded images" functions)

Menu & Functions

File Menu
Open Text Log	Open a text message log (the ".log" file type must be associated with a program)
Open Image Folder	Open png(embedded images) file folder in ipmsg log folder.
Open Attached File History Folder	Open the folder where the attached file/dir history is saved as shortcuts. These shortcuts are used when opening attached files of past messages from the LogViewer.
Open AutoSaved Folder	Open AutoSaved Folder for attached files/dirs.
Import/Remove logs...	Import(or remove) ipmsg text log files for the LogViewer. If text log format is too old, it may not be able to separate username/hostname/groupname/uid/IPaddress. (In that case, right-click the message and modify its header (== other messages that have the same header will be modified, too), or remove the imported data, reformat the text log, and import it again.)
Write logs to a Text file	Output all log information as text.
DB Prefetch	Load log-DB file(ipmsg.db) to OS cache for improving search/show performance.
DB Vacuum	Vacuum/Reindex log-DB file for reducing size and improving search performance.
DB Integrity Check	Inspect and repair the DB. Although it is not normally necessary, please try this when you have a problem such as when the log suddenly disappears.
Close	Close LogViewer
Settings Menu
Reverse Disp	Reverse the message show order.
Clear Find History	Clear Find History
Clear Find User History	Clear Find User History
Zoom image within LogViewer	When you click an image, you can choose to display it in a smaller size or in a separate window if the image does not fit in the viewer.
Fold Tail Quote	Automatically folds quotes at the end of a message.
Font Settings	Change display font (Now, same font is used for all message area in LogViewer. Only font size and thickness are changed)
IPMsg Settings	Opens the IPMsg main settings. Settings such as opening with one click can be changed from the URL/File link settings.
Color Emoji Support	UNICODE emojis are displayed in color. (Only for Win10 and later. Some fonts may not display properly.)
Show Day Of Week	For messages from the previous day or earlier, show the day of the week, such as (Mon).
Window Menu
Open New LogViewer	Open New LogViewer. Changes such as adding markers are reflected in all viewers as far as possible.
Memo Message	Add self memo like a message.
Print Menu
Output to PDF file	Output to PDF file.
Help Menu
Help	Open Viewer Help(this document).
Tips	Open Tips section in Help.
Support Forum	Open the support forum.
Latest ver URL	Open the latest version URL.

ToolBar
Jump to latest message button	Jump to latest message. Then it enters auto-scroll mode and the arrow icon changes to a dashed arrow. (with Shift key, jump to oldest message)
Switch to title only	Toggle Normal / Title only mode
Open New LogViewer	Opens a new LogViewer window (same as "Open New LogViewer" in the Window menu).
User filter ("All Users")	Narrow selected user message. (Pushing "User" button in a title has the same effect.) Pressing the small pen button next to it switches to manual input mode. (Narrows by partial match of username/uid/hostname)
Show Period "Entire period"	Selecting the pull-down menu allows you to view logs for the past year, etc.
Search string field	Start realtime string search and jumping to a message that contains the string. Pressing the Return key jumps to the next found message. Pressing Shift+Return jumps to the previous found message. If the "Check mark" is checked, only hit messages are shown. Complex search: "AAA BBB" means to search the messages that contain both "AAA" and "BBB". "AAA OR BBB" means to search the messages that contain "AAA" or "BBB".
Favorite narrowing	Narrow favorite checked messages.
Marker/Comment narrowing	Narrow markered/commented messages. (Mark: Using right click menu in selected sentence. Comment: Using "..." button in the right side of message titlebar)
Narrow embedded images	Narrow embedded image messages.
Narrow attached files	Narrow file attached messages.
Narrow unopened messages	Narrow unopened messages. The number of unopened received messages after startup is limited to 300. If it is exceeded, new messages can't be received. (Even if it is used "logviewer receive mode", hidden receive window object is created during unopen status.)

Title part of message area
Date	Show the date of send/received message. (If mouse is over this field, it will show date with day of week and seconds in bottom status field)
Arrow mark	Right arrow means sent message, and left arrow means received message. (If mouse is over this field, the arrow mark changes to a reply mark; pressing it opens the reply window)
"User" button	If it is pushed, narrow "User" messages. If it is right-clicked, reply/etc menu will be shown.
Receive "Unopened" mini button	If a received sealed message is still unopened, an "Unopened" mini button is shown at the top-right of the "User" button. If it is pushed, then the sealed message will open.
Send "Unopened" mini mark	If a sent sealed message is not opened, it will show "Unopened" mini mark in the right-top of "User" button. If the message is opened, it will be hidden.
Favorite Mark	If it is pushed a Favorite Mark in a message title, the message will be registered as "Favorite". It is also shown when narrowing with the Favorite (š) button in the toolbar.
Misc menu(...)	Select "Reply (title double click also works)", "Copy Message", "Modify Header", "Modify Message", "Delete Message", "Add Comment" menu items.

Message Area (Body)
Embedded images	Embedded (inline) images are shown as thumbnails. If it is clicked, it will be expanded. If it is double-clicked, the application associated with the ".png" extension will open it.
Add Comment	If it is right-clicked, it can be selected to add comment. If comment area is clicked, then the "Edit Comment" dialog will be opened.
Marker	"Set Marker" can be selected if the selected string area is right-clicked.
Copy	"Copy Text" can be selected if the selected string area is right-clicked.
Search Messages	It can be selected "Search Messages" can be selected if the selected string area is right-clicked., if selected string area is right-clicked.
Google Search	"Google Search" can be selected if the selected string area is right-clicked.
Reply	Open a send message window to reply. (same as title double clicking)
Embedded from Clipboard
Embedded images	When Ctrl-[V] is pressed, an "Image" can be pasted from the clipboard.
Embedded text	When Ctrl-[V] is pressed, a "Comment" can be added from the clipboard.

See here for the shortcut list

4. Settings

Settings Dialog can be opened from right-click in tasktray icon.

Basic & LAN Settings

Basic Settings
User name	Set User name
Group name	Set/Select Group name Input new group name or select group name in pulldown menu.
LAN Settings
Broadcast setup for different segments	If you want to detect members in different segments, set the broadcast address of that network here. (However, many routers block directed broadcast, so we recommend using the Member Master function (available since v4.5) instead of this field.)
Unicast required	Request other IPMsg clients to send individual presence notifications
Local segment broadcast (for IPv4 member detection)
Directed broadcast	Lists all IPv4 addresses assigned to the NICs, and sends to all of their directed broadcast addresses for member detection. (ex: if the OS has two addresses (192.168.0.1/24 and 192.168.100.2/24), it sends to 192.168.0.255 and 192.168.100.255 for member detection.)
Use both (Direct/Limited)	In addition to Directed broadcast, also sends to 255.255.255.255 (Limited broadcast) for member detection
IPv4/IPv6 mode
IPv4 mode	Run in IPv4 mode
IPv6 mode	Run in IPv6 mode
IPv4/IPv6	Run in IPv4/IPv6 dual mode
IPv6 multicast (for IPv6 member detection)
SiteLocal	Send to ff15::979 as multicast address for member detection. (If your site routers can use IPv6 multicast, over router member detection will be available.)
LinkLocal	Send to ff02::1 as multicast address for member detection. (member detection is available in local segment only)
Site/LinkLocal dual	use SiteLocal and LinkLocal
Misc
Language	Select the UI language (System/Auto, “ú–{Œê, English). (need to restart)

Member Master Settings (v4.5 or later)

This function is to detect members over routers.
If only one PC becomes a Master in the entire LAN and one or more PCs use/relate to the Master in each segment, Auto detecting members function is enabled.

Even other-OS versions can get the latest user list of the entire LAN by pressing the "Refresh" button.
(With v4.5 or later, the latest list is basically maintained without pressing "Refresh".)

Select mode
Not Use	Not use Master Mode
Use Member Master	Set Master's IP address(or FQDN). It receives member information from the Master. It also accepts requests from the Master to collect member information in its own segment. One or more PCs running in "Use Member Master (=cooperate with the master)" mode are required in each segment. (They work cooperatively) Please set as many PCs as possible (other than the master) to "Use Member Master".
Become a Master	Become a Member Master. Only one master should exist in the entire LAN. Basically, the Master's IP address should be a fixed address. The master collects member information periodically, and if a change is detected, it sends notifications to each segment. (Refresh period can be set in "Refresh Interval (min)". default: 3min. If an IPMsg disappears without sending an exit notification, it appears to be still present until the next periodic refresh.) One or more PCs that Use/Relate to a master(=Agent) in each segments are required.

Ref) As shown below, a Master PC and Use-Master PCs (Agents) cooperate to keep the member status up to date with minimal packets.

Activity Image

Detail Settings

Balloon/Toast Notification
Receive Notify	Specify duration time(sec) at receive notification
Open Notify	Specify duration time(sec) at open msg notification
Do not display user information	(As it is)
Links to Windows Control Panel
Toast Notification	Open Windows toast notification settings. (If IPMsg toast notification is disabled here, toasts will not be shown regardless of the above settings.)
Notification Area Icon	Open Windows notification area icon settings. (We recommend always showing the icon.)
HotKey settings
Use Hotkey	Open send/recv/logview window by shortcut key
Misc
Change Send/Reply → Fire/Intercept	Back to original label(1st beta in 1996)
Icon	Change main/tasktray Icon
RevIcon	Change recv/absence Icon

Send Window

DelaySend
Use Send Queue when a receiver is stopped.	If the receiver's PC is stopped, the message is saved in the send queue. It will be sent when the receiver is active. ("IPMsg Delayed Send:DATE" will be added at the end of the message) Inactive users are shown as gray in the send screen. Users who were active within the past month will be displayed. (When you want to hide, select user → RightClick → PrioritySettings → Move to No Display) (If you use this function, please use logging, otherwise inline images may not be sent at delayed sending)
Show at the end	Show inactive users at the end of the user list.
Priority users only	Show only inactive users with priority settings.
Show only for users within the last N weeks	Show only inactive users who were active within the past N weeks
Send Window
1 Click Open SendDlg	Open Send Dlg by 1click in tasktray icon
IME auto ON	Enable IME at SendDlg opened
Narrow Userlist at reply	Show original addressees in userlist at replying. (if the "+" mini button next to the user list is clicked, all users are shown)
Prevent missend	If the reply destination differs from the "original addressees()", the "Send" button temporarily changes to "Confirm". Pressing "Confirm" once returns it to the "Send" button. (() original addressees: the "sender + recipients (other than yourself)" of the original message)
Set caret to the end at replying	(As it is)
Don't quote trailing DblQuoted(>>) lines	(As it is)
Quoted Prefix	Specify quote string at replying. We recommend not to modify it, because it affects the fold action in the LogViewer.
UserHistoryNum	Specify the number of user history in right click menu of SendDlg

Recv Window

Recv Window
NonPopup Receive	Change "popup" to "blink tasktray Icon" at receiving
Quoted check	(As it is)
Open LogViewer when trayicon is clicked at recv	Open the LogViewer instead of the Receive Window
Show LogonName	(As it is)
Show IP address	(As it is)
Don't close RecvDlg when replying	(As it is)
No recv sound	(As it is)
Restore unopened msgs after restart	(As it is)
Sound	(As it is)
File attached RecvDlg without message will close automatically after files are received	(As it is)

TaskTray

TaskTray
Confirm IPMsgIcon in TaskTray at Starting	Attempts to set IPMsgIcon to show in the TaskTray at starting. If that fails, the settings dialog will be displayed.

Image/Capture

Embedded image in a message
Always show directly	Show inline images in RecvDlg, directly
Show directly if priority user	If a sender is display priority user in SendDlg, show inline images in RecvDlg, directly
Always show via Image button	(As it is)
Display (area specified) Capture
Minimize Send Message Dialog as default	(So that the Send window does not interfere with the capture)
Clipboard check as default	Copy image to Clipboard at finishing to capture
Save check as default	Open save image dialog at finishing to capture

URL/File Link

Link behavior
One click open	Open a link by single click. (default: double click is needed)
One click open (viewer only)	Open a link by single click in log viewer, and open a link by double click in send/recv window.
Link targets are only URL	Show only URL-link, not File-link. (Even if this is enabled, due to the implementation, UNC paths and file:// are still shown as links outside the LogViewer, but clicking them does not open anything.)
Permitted file extensions for clicking a file link	Set the file extensions that open without a confirmation dialog when a file link is clicked. (Same behavior as double-clicking in Explorer)

Log Setting

Logging
Logging available	(As it is)
LogFile	Specify a filename of send/recv message logs. And also, a dbfile(ipmsg.db) for logviewer will be created in same folder. And also, inline image(.png) files will be stored in ipmsg_img subfolder of LogFolder. Shortcuts to attached files are stored in the ipmsg_dllinks subfolder. Auto-saved attached files are stored in the AutoSave subfolder.

Auto FileDownload

Auto Save
Enable to download attached files automatically	(If a message is opened (or its body is displayed), it is excluded from auto-save. In that case, download it manually.)
Auto download folder	(If not specified, "(LogFile folder)\AutoSave" is used)
Limitation by disp priority	AutoSave can be limited to display-priority users only.
Download size limitation(MB)	Specify the limit of total download size Downloaded sizes are added up while IPMsg is not being operated by the user (This prevents huge or numerous files from being auto-received and filling up the disk)
Grace sec of starting auto downloading	(As it is)
Allow to download folders	AutoSave is enabled, even if it is a folder. But if the total downloaded file/folder size exceeds the limitation size, the folder transfer will be discontinued even midway. (In this case, it can still be re-downloaded manually as long as the sender's IPMsg has not been restarted)

Remote reboot

Remote Reboot
Allow remote Reboot	If a message containing the displayed "ipmsg-cmd:..." in its body is received, this machine will reboot after the reboot confirmation dialog times out (15 sec)
Refresh	Change the reboot message command("ipmsg-cmd:...")
Remote Shutdown
Allow remote Shutdown	If it is received "ipmsg-cmd:...", this machine will shut down after the shutdown confirmation dialog times out (15 sec)
Refresh	Change the shutdown message command("ipmsg-cmd:...")
Remote Terminate IPMsg
Allow remote terminate IPMsg	If it is received "ipmsg-cmd:...", this ipmsg will be terminated when a terminate confirm dialog is timeout(15sec)
Refresh	Change the terminate message command("ipmsg-cmd:...")

(e.g. when you want to reboot a machine remotely due to some trouble, or reboot it easily through multi-hop RDP sessions)

RecvTrans (Slack or etc)

Transfer messages received mainly while the screen is locked or the screensaver is running to Slack or another server.
To transfer to Slack, you need to set up Slack Incoming Webhooks and get the webhook URL.
If you want to transfer to another server, it is required to describe URL and POST message.

Common Settings
Transfer Mode	Select the transfer mode. In "Transfer (at LockScreen)" mode, unopened messages that had accumulated when the screen was locked are also transferred.
Slack or General	Select Slack or General
Test	Transfer test message to slack or another server. If an error occurs, it is written in the text area in right side. Ref) Slack handling errors
for Slack
incoming webhook URL	Describe /Txxxxxx/Bxxxxx/xxxxxxx after https://hooks.slack.com/services URL Ref) Slack Incoming Webhooks
#channel/@username	Specify #channel or @username.
for General
URL	Describe URL that you want to transfer to
POST	Describe POST data. $(sender) and $(msg) are replaced with the actual sender name and message body.

Auto Update

Auto Update
Regularly check the latest version	Regularly checks for the latest version and, if a new version is released, updates IPMsg automatically.
Check the latest version, but no install	If a new version exists, a balloon notification is shown; clicking it opens the update confirmation dialog, and pressing OK starts the update.
Check Update	Check the latest version now, and if new version exists, the button label will change to "Start to Update"
(Mechanism / technical details)
Safe updating is achieved as follows, without depending on the safety of the communication path or the server (even though https is used). 1) Periodically downloads the "latest version data" (https://ipmsg.org/ipmsg-update.dat). (This data contains, in IPDict format, "version information for the 32bit/64bit editions", "installer size and SHA-256 hash", "installer path within ipmsg.org (/archive/ipmsg5xxx_installer.exe etc.)", and "a digital signature (SHA-256 + RSA 2048bit) of this data") 2) After the download, its digital signature is verified with the official IPMsg public key embedded in IPMsg. 3) If verification succeeds, the version is compared with IPMsg's own version. 4) If a newer version exists, the installer is downloaded from the path described in the "latest version data". 5) After the download succeeds, the content is verified against the hash value and size in the "latest version data". 6) If verification succeeds, the installer is saved as ipmsgupd64(or32).exe next to ipmsg.exe and executed with the /SILENT option. (If the ipmsg.exe folder is not writable, the installer is saved to a temporary directory and started normally, prompting manual installation.)

Settings/Misc

Export Settings
Export settings to .reg file	(As it is)
Windows Firewall
Don't confirm Windows Firewall settings at start	In current version, ipmsg confirms Windows Firewall Settings at starting. And if Windows Firewall blocks IPMsg packet, IPMsg shows "Add to firewall exception list for receive" dialog. If it is checked, this dialog will not be shown.
Experimental
Reduce task tray action at receiving	(Change "Blink" to "mini sun moving")
Enable lock with seal (old vers func. need restart)	Revives the "Lock" UI function that existed until v3.x (restart required)
Change to [Away] when desktop is inactive	When desktop inactivity is detected (e.g. screensaver started), " [Away]" is appended to the user name.

5. Ports/Registry

Normally, UDP/TCP port 2425 is used (unless a port is specified on the command line).
(If file/folder attachment, image paste, and Member Master are not used, only UDP port 2425 is used)
(These ports need to be opened when Windows Firewall etc. is enabled)

Setting is saved in the following registry key.
\\HKEY_CURRENT_USER\Software\HSTools\IPMsgEng
(If a port number is specified, IPMsg + port number)
Please terminate IPMsg before making registry changes.

Protocol specification comes with source.(Japanese)

6. Troubleshooting

Question	Solution
Cannot recognize members across routers	Since modern routers often block network-directed broadcasts, we recommend using the Member Master setting for communication across routers.
Cannot receive messages / Recipient unable to receive files/images	IP Messenger uses UDP port 2425 for member detection and message communication, and TCP port 2425 for file/image transfer. If these ports are blocked by the OS or antivirus software, IP Messenger can't detect other members or send/receive files or images. Please configure your system to allow them. (On Windows Defender, an elevation dialog will appear at startup to open these ports.)
File/Image transfers fail with download errors even though IPMsg is excluded in Windows Defender	(If existing exclusion rules are not working properly, re-registering them may help.) 1. Go to Firewall & Network Protection → Advanced Settings to open Windows Defender Firewall with Advanced Security. 2. In Inbound Rules, delete all entries labeled "IPMsg". 3. Restart IPMsg. A dialog will appear saying "Add to firewall exception list for receive." Click OK. (If the dialog does not appear, make sure Settings → Settings/Misc → Don't confirm Windows Firewall settings at start is set to OFF.)

7. CommandLine

Since v4.5, a special command (ipcmd.exe) has been added.
(Its parent folder can be opened by right click menu in task tray icon(

) → Latest & Help, etc → Installed Folder)

With ipmsg.exe running (resident), ipcmd.exe can get/set the absence mode, send messages, and also receive messages.
(By writing a batch file that combines recv and send, forwarding-like operation is also possible.)

Format: ipcmd [/port=N] [/nic=ipaddr] [/nostat] sub command...

sub command
Get absence mode	getabs
Set absence mode	setabs (0\|1\|...\|N)
Get UserList	list [/all]
Refresh UserList	refresh [/noremove]
Send a message	send [/file=path1 /file=path2...] [/noseal] "((uid\|ipaddr\|ALL)[,uid...]\|/userfile=path)" ("msg_body" \| /msgfile=path)
Receive a message	recv [/msgfile=path]
Status	state
Terminate IPMsg	terminate

ex.1) Send a message: ipcmd send "shirouzu-<09b167745f2bdf56>,user2-<7764219b1adac4d0>" test
(For delayed sending to inactive users, specify them by Logon ID)
ex.2) Get userlist(with inactive users): ipcmd list /all
ex.3) Set absence mode: ipcmd setabs 1

ipmsg.exe command line

Format: ipmsg.exe [port] [/NIC ipaddr] [/NICID n] [/NICLIST] [/IPCHANGE_REFRESH[2|3]]

By default UDP/TCP port 2425 is used, but you can open a separate session by specifying a port number on the command line.
IPMSG can run at multiple sessions.
For example, using [ipmsg.exe 2426] command, you can contact only people who are using 2426 port.
(When running multiple instances, specify a different log directory for each; if they share one, the log may not be written when messages arrive at the same time.)

/IPCHANGE_REFRESH ... Notify nearby members of the address change approximately 10 seconds after the change of your IP address.
/IPCHANGE_REFRESH2 ... Perform an action similar to pressing the refresh button (but slightly lighter) approximately 10 seconds after the change of your IP address. (Be careful of increased traffic if your IP address changes frequently)
/IPCHANGE_REFRESH3 ... Perform the refresh button action approximately 10 seconds after the change of your IP address. (Be especially careful of increased traffic if your IP address changes frequently)

8. Support

Any bug report, suggestion and recommendations are welcome in the support forum. (The support forum is the only official support entry)
For bug reports, please describe the following in as much detail as possible.
software version, operating system, what happened, and how to reproduce it.

9. Tips/Shortcut

Function	Details
Almost All Windows	To close a window, Shortcut(CTRL + [W]) can be used.
Open Send/Recv/LogView Dialog	It is convenient to use the shortcut keys. (It is assigned CTRL + ALT + [S][R][E], as default) And in send/recv/LogView dialog, you can use BOSS key(Ctrl-[D])
Send Dialog	Ctrl-[F] is User incremental Search It is convenient to set display priority from the right-click menu of the user list. Double-clicking a user opens the log for that user. The list of recently sent users ("User History") is also available from the right-click menu of the user list. If you right-click an image, it can be re-edited or saved as an image file. If you send while holding Shift + Ctrl + right-click, the receiver's IPMsg version is retrieved. If the Refresh button is clicked with the Ctrl key, the user list is refreshed without removing existing entries.
Receive Dialog	If you right-click an image, it can be saved to a file with a specified name. An image can be dragged & dropped into the Send Dialog.
LogViewer	Various keyboard shortcuts are available. [Space][Ret] Go to next message (with Shift-key, go to previous message) Ctrl-[T] or [Home] Jump to the top of messages (oldest message) Ctrl-[B] or [End] Jump to the end of messages (newest message) Ctrl-[R] Reply (only if an explicit current message() exists) Ctrl-[S] Open Send Dialog Ctrl-[F] Set focus to the Search field (toggle) Ctrl-[N] Show only search results (toggle) Ctrl-[U] User string search (toggle) Ctrl-[Q] Title Only mode (Toggle) Ctrl-[C] Copy selected area to clipboard Ctrl-[V] Paste from clipboard In the Search field, you can use AND/OR/NOT search. AND: "AAA BBB" OR: "AAA OR BBB" NOT: "AAA NOT BBB" (NOT can't be used at the top of the field) () Explicit current message() = selected by mouse click, moved to by [Ret], etc. () Current message has a gray line in the left of header

10. History

The commercial version of IP Messenger Pro is now available.
Various compliance features are included.
With the release of the Pro version, the special version is no longer offered.

Version	Details
v5.8.6	Faster LogViewer rendering (drawing cache eliminates scroll stutter). Fixed slight text jitter on text selection in LogViewer. Workaround for FirewallAPI exceptions in some environments. Corrections to help and dialog text.
v5.8.4	Various security enhancements. - Stricter DLL loading (pre-validation of iptoast.dll, added /DEPENDENTLOADFLAG:0x800) - Enabled Control Flow Guard (/guard:cf). - Enabled EH Continuation Metadata (/guard:ehcont). - Enabled ASLR / High Entropy ASLR (/DYNAMICBASE, /HIGHENTROPYVA). - (Already enabled: /CETCOMPAT (Shadow Stack), /GS, /NXCOMPAT (DEP), /SAFESEH (x86), /DELAYLOAD, SetDefaultDllDirectories)
v5.8.3	Fixed some resource leaks. Various stability improvements.
v5.8.1	Enhanced the screen-capture marker. (Custom colors can now be specified via the color-chooser dialog.) Various stability improvements.
v5.8.0	Images larger than the monitor size can now be re-edited. Add /IPCHANGE_REFRESH to the command line arguments. Update SQLite (3.53.0) and zlib (1.3.2).
v5.7.6	Added a size display tooltip for screen capture.
v5.7.5	Added "Remove from User History List" to the Priority Settings menu when right-clicking on the user list in the Send Window. (For immediately deleting user names that are not expected to log in again) Improved behavior around standby/hibernate.
v5.7.3	Added option to "File attached RecvDlg without message will close automatically after files are received." (Settings → Recv Window) If the sender's IP address changes between receiving and opening the message, a notification of opening will be sent accordingly.
v5.7.2	Fixed an issue where double-clicking a URL on the send/receive screen would sometimes not work.
v5.7.1	Added "day of week" to the message header in the LogViewer. (Optional) Improved handling of the task tray icon on Win11.
v5.6.0-19	In screen capture, pressing Shift+Ctrl now selects the window directly under the cursor as the capture range. Added "DB Integrity Check" menu item to LogViewer. File attachments support symbolic link files. (transferred as normal files) Changed the file attachment function so that it continues to work even if there is a file that cannot be opened. Japanese mode can now be selected even on non-Japanese OS. Improved message reachability in multiple NIC environments. Enhanced security with Shadow Stack (CETCOMPAT). Fixed an issue where the ipcmd.exe send command sometimes failed to send. Update zlib and SQLite.
v5.5.0	Added range selection & duplicate mode in screen capture. (Ctrl+C, Ctrl+V to exchange clipboard)
v5.4.0	Added period filtering function to LogViewer.
v5.3.2	Fixed issue with incomplete PDF printing in LogViewer (v5.3.1 only)
v5.3.1	Color Emoji support in LogViewer (Win10 or later) (Can be disabled from LogViewer → Settings, since it may not render well depending on the selected font) Fixed the /NIC option not working (v5.3.0 only; IPMsg restart required)
v5.2.0 - v5.2.3	Color emoji support in Send/Recv Edit Area (Only 64bit Microsoft365 installed environment; not supported in LogViewer) Color emoji support is now optional (Settings → Detail Settings) due to problems in some environments. Fixed an exception that could occur when sending from the command line.
v5.1.1 - v5.1.3	Fixed the problem of the comment icon not appearing in LogViewer. Changed generic receive transfer with GET method to POST method. Fixed a crash that sometimes occurred during marker operations in LogViewer. Fixed unicode logon name issue.
v5.1.0	Add PDF output from LogViewer (Win10 only) Add /userfile= option to ipcmd send command (to specify a uid list).
v5.0.3	Fixed an issue where the exit user would not disappear with the refresh button (v5.0.0 - v5.0.2) Member Master can now be used in environments where fragment packets do not pass. (The agent for each segment also needs to be updated to v5.0.3 or later.)
v5.0.1 - v5.0.2	Improved arrow annotations in screen-capture drawing mode. Save to clipboard is now the default for screen capture.
v5.0.0	Improve LogViewer (Multi-Tab, Show 1x image, re-editing image, etc) Speeding up file/folder transfer (Import a part of FastCopy technology) Improve capture/drawing mode.
v4.00 - v4.99	Add Member Master function Add built-in LogViewer (inline images, full-text search, user filtering) Add special command(ipcmd.exe). (It can set/get absence mode, receive messages, send messages with attached files, etc. from the command line) Support auto-selecting all addressees when replying to a multiple-addressee message. Support RecvMsg Transfer mode. (Transfer to Slack or etc) Add Send Queue mode (Delayed Send) when the receiver is inactive. Support Auto Update. Added mis-send prevention option (detects addressee changes). Support SHA-256 signing. Obsolete old weak encryption mode (RSA512bit/RC2-40bit)
v3.00 - v3.64	Support auto download option for attached files. Support IPv6 multicast Support remote reboot/shutdown. Support screen capture & embedded image in message Support RSA2048/AES256bit encryption. Support RSA2048/SHA-1 digital sign/verify & userid extension(public-key fingerprint).
v2.00	File/Folder Transfer function support, Encrypted communication (RSA+Blowfish) support.
v1.31	English version support(97/09/01)
v1.00	Official public version (1996/08/19)

IP Messenger v5.8.6