Based on: 
* https://forum.pfsense.org/index.php?PHPSESSID=c93krctgp8ueben00q7udbhqs6&topic=103841.105
* https://www.reddit.com/r/PFSENSE/comments/7n300s/solved_slow_internet_throughput_on_rogers_1gbs/

1. Download FreeBSD 11.1 VMDK and create a VM with it as HDD:

    https://download.freebsd.org/ftp/releases/VM-IMAGES/11.1-RELEASE/amd64/Latest/FreeBSD-11.1-RELEASE-amd64.vmdk.xz
    
1. Get FreeBSD source tree and uncompress it to /usr/src:
```
    fetch -o /tmp ftp://ftp.freebsd.org/pub/`uname -s`/releases/`uname -m`/`uname -r | cut -d'-' -f1,2`/src.txz
    tar -C / -xvf /tmp/src.txz
```
1. Download Realtek latest driver:

    http://www.realtek.com.tw/downloads/downloadsView.aspx?Langid=1&PNid=5&PFid=5&Level=5&Conn=4&DownTypeID=3&GetDown=false

1. Uncompress driver:
```
    tar xvzf 0007-rtl_bsd_drv_v194.01.tgz
```
1. Make driver:
```
    cd rtl_bsd_drv_v194.01
    make
```
    1. If the last command fails, change the following line in file if_re.c

    From: `#include <dev/re/if_rereg.h>`
    
    To: `#include if_rereg.h"`

1. Copy the file if_re.ko to the /boot/kernel folder in pfSense device.

    `scp if_re.ko root@<pfSense device IP>`

1. Change file permissions in if_re.ko file accessing through SSH to pfSense.

    `chmod 555 /boot/kernel/if_re.ko`

1. Modify /boot/loader.conf.local file and add the following line at the end of the file: `if_re_load="YES"`
  - Through console: `vi /boot/loader.conf.local`
  - Through web:  Diagnostics > Edit File and click Load. When finished editing click Save.

1. Reboot pfSense.

1. After restart, verify if module is installed through ssh. Example execution:
```
    [2.4.2-RELEASE][root@pfSense.local]/root: kldstat
        Id Refs Address            Size     Name
         1    7 0xffffffff80200000 2c3ea98  kernel
         2    1 0xffffffff82e3f000 80900    if_re.ko
         3    1 0xffffffff83021000 46c6     cryptodev.ko
```