How US defense secretary Hegseth circumvents the official DoD communications equipment

(Updated: May 1, 2025)

US defense secretary Pete Hegseth appears to have a private computer in his office that is linked to the public internet. He wanted this computer to use the messaging app Signal, which is the preferred method of communication among Trump's government officials.

Here I will look at the secretary of defense's official communications equipment and the SecDef Cables communications center. There's also a photo in which Hegseth's private computer can be recognized.

US defense secretary Pete Hegseth in his office in the Pentagon, January 30, 2025
(Still from a video message on X, formerly Twitter)

Hegseth's government equipment

Like his predecessors, Trump's defense secretary Pete Hegseth has access to a range of secure and non-secure telephone and computer networks. The equipment is installed at a table behind his back, when sitting at his big writing desk in the Pentagon.

In the photo above we can see that equipment in a set-up that has basically been unchanged since Chuck Hagel, who was Obama's secretary of Defense from 2013 to 2015. In the photo of Pete Hegseth we see from left to right:

- On top of a wooden stand sits a Cisco IP Phone 8841 with a 14-key expansion module. This phone is part of the Crisis Management System (CMS), which connects the President, the National Security Council, Cabinet members, the Joint Chiefs of Staff, intelligence agency watch centers, and others. Its bright yellow bezel indicates that it can be used for conversations up to Top Secret/Sensitive Compartmented Information (TS/SCI).

- Below the CMS phone on the wooden stand is (hardly visible) an Integrated Services Telephone-2 (IST-2), which can be used for both secure and non-secure phone calls. This phone belongs to the Defense Red Switch Network (DRSN), also known as the Multilevel Secure Voice service, which connects the White House, all military command centers, intelligence agencies, government departments and NATO allies.

- Right in front of the IST-2 is another Cisco IP Phone 8841 with a 14-key expansion module, but this time with a green bezel, which indicates that it's for unclassified phone calls. This phone is part of the internal telephone network of the Pentagon and replaced an Avaya Lucent 6424 executive phone, which can be seen in the following photo from 2021, along with a better view on the other phones:

Former secretary of defense Lloyd Austin in his Pentagon office in 2021,
with a Cisco IP phone with yellow bezel for the CMS and
an IST-2 phone with many red buttons for the DRSN.
(DoD photo - click to enlarge)

- Besides the telephones there are two computer screens, both with a bright green wallpaper, which again indicates that they are connected to an unclassified network, most likely NIPRNet. In the photo of Lloyd Austin's office we see that there's also a KVM switch which is used to switch securely to the SIPRNet (Secret) and JWICS (Top Secret/SCI) networks, using the same keyboard, video and mouse set.

- Finally, at the right side of the table there are two Cisco Webex DX80 videoteleconferencing screens. The one at the right has a yellow label, which indicates that it's approved for Top Secret/SCI and most likely belongs to the Secure Video Teleconferencing System (SVTS), which is part of the aforementioned Crisis Management System (CMS). The other screen might then be for videoconferences at a lower classification level.

> See also: US military and intelligence computer networks

Hegseth's personal computer

Despite the wide range of options for communicating via the proper and secure government channels, secretary Hegseth insisted on using Signal. Apparently it wasn't allowed or possible to install this app on one of the government computers, nor on a smartphone that is approved for classified conversations.

Therefore, Hegseth initially went to the back area of his office where he could access Wi-Fi to use Signal, according to AP News. It's not clear whether he used a private laptop or his personal smartphone, both of which would have been strictly forbidden to use in secure areas like this.

> See: The equipment that Trump's national security team should have used

Somewhat later, Hegseth requested an internet connection to his desk where he could use a computer of his own. This line connects directly to the public internet and bypassed the Pentagon's security protocols. This new computer must be the one that can be seen in the photo below, as it wasn't there yet on February 21 and has no labels that indicate its classification level:

US defense secretary with a new desktop computer on his desk, March 20, 2025
(DoD photo, see also this video message on X)

Some other employees at the Pentagon also use direct lines to the public internet, for example when they don't want to be recognized by an IP address assigned to the Pentagon. That's risky because such a line is less well monitored than NIPRNet, which allows limited access to the outside internet.

At his new desktop computer, Hegseth had Signal installed, which means he effectively 'cloned' the Signal app that is on his personal smartphone. He also had interest in the installation of a program to send conventional text messages from this personal computer, according to some press sources.

The move was intended to circumvent a lack of cellphone service in much of the Pentagon and enable easier communication with the White House and other Trump officials who are using the Signal app.



SecDef Cables

It is remarkable to what great lengths Hegseth went to use the Signal app, because as defense secretary he has his own communications center which is specialized in keeping him in contact with anyone he wants. This center is commonly called SecDef Cables and is part of Secretary of Defense Communications (SDC) unit.

SecDef Cables provides operational information management and functions as a command and control support center. It is staffed by 26 service members and 4 civilians. They provide "comprehensive voice, video, and data capabilities to the secretary and his immediate staff, regardless of their location, across multiple platforms and classifications."

Furthermore, SecDef Cables serves as a liaison to the National Military Command Center (NMCC), the White House Situation Room, the State Department Operations Center and similar communication centers. Finally, Cables provides the connections for the Defense Telephone Link (DTL), which is a lower-level hotline with military counterparts in about 25 countries, including Russia and China.

> See also: Bilateral Hotlines Worldwide

Secretary of Defense Communications recruitment video from 2023

Links and sources
- emptywheel: Whiskey Pete’s Dirty Desktop (April 25, 2025)
- AP News: Hegseth had an unsecured internet line set up in his office to connect to Signal, AP sources say (April 24, 2025)
- The Washington Post: Hegseth had Signal messaging app installed on an office computer (April 24, 2025)

See also the comments on Hacker News