headless x11vnc - higher resolution

I'm trying to get my Ubuntu box to run at a higher resolution than the default 1024x768. As you can see from the log, i'm using integrated Intel video drivers. I've tried adding an xorg.conf with a dummy monitor but I still get the default resolution. I've also tried specifying the geometry in the x11vnc.service. Then I added a custom dummy monitor config, as below. /usr/share/X11/xorg.conf.d/10-monitor.conf Section "Monitor" Identifier "Monitor0" Option "Enable" "true" Option "DPMS" "false" DisplaySize 400 300 EndSection Section "Device" Identifier "Device0" Driver "intel" EndSection Section "Screen" Identifier "Screen0" Device "Device0" Monitor "Monitor0" DefaultDepth 24 SubSection "Display" Depth 24 Modes "1920x1080" "1600x1200" "1280x768" EndSubSection EndSection File: /var/log/Xorg.0.log [ 3.564] (II) Module glx: vendor="X.Org Foundation" [ 3.564] compiled for 1.18.4, module version = 1.0.0 [ 3.564] ABI class: X.Org Server Extension, version 9.0 [ 3.564] (==) AIGLX enabled [ 3.564] (II) LoadModule: "intel" [ 3.565] (II) Loading /usr/lib/xorg/modules/drivers/intel_drv.so [ 3.567] (II) Module intel: vendor="X.Org Foundation" [ 3.567] compiled for 1.18.4, module version = 2.99.917 [ 3.567] Module class: X.Org Video Driver [ 3.567] ABI class: X.Org Video Driver, version 20.0 [ 3.567] (II) intel: Driver for Intel(R) Integrated Graphics Chipsets: i810, i810-dc100, i810e, i815, i830M, 845G, 854, 852GM/855GM, 865G, 915G, E7221 (i915), 915GM, 945G, 945GM, 945GME, Pineview GM, Pineview G, 965G, G35, 965Q, 946GZ, 965GM, 965GME/GLE, G33, Q35, Q33, GM45, 4 Series, G45/G43, Q45/Q43, G41, B43 [ 3.567] (II) intel: Driver for Intel(R) HD Graphics: 2000-6000 [ 3.567] (II) intel: Driver for Intel(R) Iris(TM) Graphics: 5100, 6100 [ 3.567] (II) intel: Driver for Intel(R) Iris(TM) Pro Graphics: 5200, 6200, P6300 [ 3.570] (II) intel(0): Using Kernel Mode Setting driver: i915_bpo, version 1.6.0 20160425 [ 3.570] (II) intel(0): SNA compiled: xserver-xorg-video-intel 2:2.99.917+git20160325-1ubuntu1.2 (Timo Aaltonen ) [ 3.570] (II) intel(0): SNA compiled for use with valgrind [ 3.571] (--) intel(0): gen9 engineering sample [ 3.571] (--) intel(0): CPU: x86-64, sse2, sse3, ssse3, sse4.1, sse4.2; using a maximum of 2 threads [ 3.571] (**) intel(0): Depth 24, (--) framebuffer bpp 32 [ 3.571] (==) intel(0): RGB weight 888 [ 3.571] (==) intel(0): Default visual is TrueColor [ 3.572] (II) intel(0): Output HDMI1 using monitor section Monitor0 [ 3.572] (**) intel(0): Option "Enable" "true" [ 3.572] (II) intel(0): Enabled output HDMI1 [ 3.572] (II) intel(0): Output HDMI2 has no monitor section [ 3.572] (II) intel(0): Enabled output HDMI2 [ 3.572] (II) intel(0): Output DP1 has no monitor section [ 3.572] (II) intel(0): Enabled output DP1 [ 3.572] (--) intel(0): Using a maximum size of 256x256 for hardware cursors [ 3.572] (II) intel(0): Output VIRTUAL1 has no monitor section [ 3.572] (II) intel(0): Enabled output VIRTUAL1 [ 3.572] (==) intel(0): TearFree disabled [ 3.572] (**) intel(0): Display dimensions: (400, 300) mm [ 3.572] (**) intel(0): DPI set to (65, 65) [ 3.572] (II) Loading sub module "dri2" [ 3.572] (II) LoadModule: "dri2" [ 3.572] (II) Module "dri2" already built-in [ 3.572] (II) Loading sub module "present" [ 3.572] (II) LoadModule: "present" [ 3.572] (II) Module "present" already built-in [ 3.572] (==) Depth 24 pixmap format is 32 bpp [ 3.575] (II) intel(0): SNA initialized with Kabylake (gen9) backend [ 3.575] (==) intel(0): Backing store enabled [ 3.575] (==) intel(0): Silken mouse enabled [ 3.575] (II) intel(0): HW Cursor enabled [ 3.575] (II) intel(0): RandR 1.2 enabled, ignore the following RandR disabled message. [ 3.576] (==) intel(0): Display hotplug detection enabled [ 3.576] (II) intel(0): [DRI2] Setup complete [ 3.576] (II) intel(0): [DRI2] DRI driver: i965 ^G Get Help ^O Write Out ^W Where Is ^K Cut Text ^J Justify ^C Cur Pos ^Y Prev Page M-\ First Line M-W WhereIs Next ^^ Mark Text M-} Indent Text M-U Undo ^B Back ^X Exit ^R Read File ^\ Replace ^U Uncut Text ^T To Spell ^_ Go To Line ^V Next Page M-/ Last Line M-] To Bracket M-^ Copy Text M-{ Unindent Text M-E Redo ^F Forwards /lib/systemd/system/x11vnc.service: [Unit] Description="x11vnc" Requires=display-manager.service After=display-manager.service [Service] ExecStart=/usr/bin/x11vnc -xkb -norc -forever -shared -display :0 -xrandr -auth guess -rfbauth /etc/x11vnc.pass -localhost -o /var/log/x11vnc.log ExecStop=/usr/bin/killall x11vnc Restart=on-failure Restart-sec=2 [Install] WantedBy=multi-user.target