diff --git a/GRUB Guide/2. Setting QEMU bridge.md b/GRUB Guide/2. Setting QEMU bridge.md
index bbdf05e..292b70b 100644
--- a/GRUB Guide/2. Setting QEMU bridge.md
+++ b/GRUB Guide/2. Setting QEMU bridge.md
@@ -1,30 +1,25 @@
-[Âü°í»çÀÌÆ®](http://www.joinc.co.kr/modules/moniwiki/wiki.php/Site/cloud/Qemu/Network)
-
-¿ìºÐÅõ¿¡¼ Bridge ³×Æ®¿öÅ© ±¸Ãà
--------------------------------------------------------------------
-¿ìºÐÅõ¿¡ ºê¸´Áö ³×Æ®¿öÅ©¸¦ ±¸ÃàÇϱâ·Î Çß´Ù. ¾Æ·¡ÀÇ °úÁ¤À» °ÅÄ£´Ù.
+**Âü°í »çÀÌÆ®**
```
-1. È£½ºÆ® ºê¸´ÁöÀÎ br0¸¦ ¸¸µç´Ù.
-2. br0¸¦ eth0 Æ÷Æ®¿¡ ¸µÅ©ÇÑ´Ù.
-3. VMÀ» À§ÇÑ tap µð¹ÙÀ̽º 2°³¸¦ ¸¸µç´Ù. À̸§Àº tap1°ú tap2·Î Çß´Ù.
-4. br0¿¡ tap1, tap2, eth0À» ¹´Â´Ù.
+http://www.joinc.co.kr/modules/moniwiki/wiki.php/Site/System_management/dhcp
+http://www.joinc.co.kr/modules/moniwiki/wiki.php/Site/System_management/PXEBoot
```
-###*1. brctlÀ» ÀÌ¿ëÇؼ ºê¸´Áö¸¦ ¸¸µç´Ù.*
+**Çʼö**
+```
+- sudo apt-get update
+- sudo apt-get upgrade
```
-# brctl addbr br0
-# ifconfig br0 up
+
+# sudo brctl addbr br0
+# sudo ifconfig br0 up
```
-###*2. ºê¸´Áö ÀÎÅÍÆäÀ̽º¸¦ ¼³Á¤ÇÑ´Ù.*
-1. eth0 °ú ºê¸´Áö ÇÑ´Ù.
-2. dhcp¸¦ ÀÌ¿ëÇؼ ºê¸´ÁöÀÇ ³×Æ®¿öÅ©¸¦ ¼³Á¤ÇÑ´Ù. dhcp ÆÐŶÀº eth0À» Ÿ°í ³ª°¡¼ ºê·Îµåij½ºÆà µÈ´Ù.
+###*2. ºê¸´Áö ÀÎÅÍÆäÀ̽º¸¦ ¼³Á¤*
```
-# vim /etc/network/interfaces
+# sudo vim /etc/network/interfaces
```
-¢º interfacesÀÇ ³»¿ë
+**interfaces¿¡ Ãß°¡ÇÒ °Í**
```
-# cat /etc/network/interfaces
auto lo
iface lo inet loopback
@@ -35,62 +30,153 @@ iface br0 inet dhcp
bridge_fd 0
bridge_maxwait 0
```
-
+1. eth0 °ú ºê¸´Áö ÇÑ´Ù.
+2. dhcp¸¦ ÀÌ¿ëÇؼ ºê¸´ÁöÀÇ ³×Æ®¿öÅ©¸¦ ¼³Á¤ÇÑ´Ù. dhcp ÆÐŶÀº eth0À» Ÿ°í ³ª°¡¼ ºê·Îµåij½ºÆà µÈ´Ù.
+
###*3. ºê¸´Áö ÀÎÅÍÆäÀ̽º¸¦ ¿Ã¸°´Ù.*
```
-# ifup br0
+# sudo ifup br0
```
-###*4. eth0ÀÌ Çß´ø ³×Æ®¿öÅ© ÀÎÅÍÆäÀ̽ºÀÇ ¿ªÇÒÀº ¾ÕÀ¸·Î br0ÀÌ ÇÏ°í eth0Àº ¹°¸®ÀûÀÎ µð¹ÙÀ̽º¸¦ ¸µÅ©Çϱâ À§ÇÑ ¿ªÇÒ¸¸À» ÇÑ´Ù. µû¶ó¼ eth0ÀÇ ³×Æ®¿öÅ© ¼³Á¤À» ¾ø¾Ø´Ù.*
+###*4. eth0ÀÇ ³×Æ®¿öÅ© ¼³Á¤À» ¾ø¾Ø´Ù.*
+ÀÌÀ¯ : eth0ÀÌ Çß´ø ³×Æ®¿öÅ© ÀÎÅÍÆäÀ̽ºÀÇ ¿ªÇÒÀº ¾ÕÀ¸·Î br0ÀÌ ÇÏ°í eth0Àº ¹°¸®ÀûÀÎ µð¹ÙÀ̽º¸¦ ¸µÅ©Çϱâ À§ÇÑ ¿ªÇÒ¸¸À» ÇÑ´Ù.
```
-# ifconfig eth0 0.0.0.0
+# sudo ifconfig eth0 0.0.0.0
```
###*5. Tap interface »ý¼º*
```
-# openvpn --mktun --dev tap1
-# openvpn --mktun --dev tap2
-# ifconfig tap1 up
-# ifconfig tap2 up
+# sudo openvpn --mktun --dev tap0
+# sudo ifconfig tap0 192.168.56.1 up
```
-###*6. ºê¸´Áö¿¡ ÀÎÅÍÆäÀ̽ºµéÀ» Ãß°¡ÇÑ´Ù.*
+###*6.ºê¸´Áö¿¡ ÀÎÅÍÆäÀ̽ºµéÀ» Ãß°¡*
```
-# brctl addif br0 tap1
-# brctl addif br0 tap2
-# brctl addif br0 eth0
+# sudo brctl addif br0 tap0
+# sudo brctl addif br0 eth0
```
-###*7. ³×Æ®¿öÅ© ºê¸´Áö Á¤º¸¸¦ È®ÀÎÇØ º¸ÀÚ.*
+###*7. ³×Æ®¿öÅ© ºê¸´Áö Á¤º¸¸¦ È®ÀÎ*
```
# brctl show
+```
+**Ãâ·Â °ª**
+```
bridge name bridge id STP enabled interfaces
br0 8000.d2a4aba39cf4 no eth0
tap1
tap0
```
-###*8. È£½ºÆ®ÀÇ ¶ó¿ìÆà ¼³Á¤À» È®ÀÎÇØ º¸ÀÚ.*
+###*8. È£½ºÆ®ÀÇ ¶ó¿ìÆà ¼³Á¤À» È®ÀÎ*
```
# route -n
+```
+**Ãâ·Â °ª**
+```
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.11.1 0.0.0.0 UG 0 0 0 br0
169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 br0
192.168.11.0 0.0.0.0 255.255.255.0 U 0 0 0 br0
```
-¢º 0.0.0.0/0À¸·Î ÇâÇÏ´Â ÆÐŶÀº br0 À¸·Î È帥´Ù. br0Àº ÀÌ ÆÐŶÀ» eth0 ÀÎÅÍÆäÀ̽º·Î º¸³¾ °ÍÀÌ´Ù.
-¢º 192.168.11.0/24·Î ÇâÇÏ´Â ÆÐŶÀº LAN ¿µ¿ª¿¡¼ ¼ÒºñµÈ´Ù.
+0.0.0.0/0À¸·Î ÇâÇÏ´Â ÆÐŶÀº br0 À¸·Î È帥´Ù. br0Àº ÀÌ ÆÐŶÀ» eth0 ÀÎÅÍÆäÀ̽º·Î º¸³¾ °ÍÀÌ´Ù.
+192.168.11.0/24·Î ÇâÇÏ´Â ÆÐŶÀº LAN ¿µ¿ª¿¡¼ ¼ÒºñµÈ´Ù.
+Å×½ºÆ®¸¦ À§ÇÑ VMÀ» ½ÇÇàÇÑ´Ù. VMµéÀÇ ³×Æ®¿öÅ© ¼³Á¤Àº DHCP·Î ÇÑ´Ù.
+
+###*9. TFTP ¼¹ö ¼³Á¤*
+```
+# sudo apt-get install tftp
+# sudo apt-get install tftpd
+# cat /etc/xinetd.d/tftp
+```
+**tftp¿¡ Ãß°¡ÇÒ °Í**
+```
+service tftp
+{
+ disable = no
+ socket_type = dgram
+ protocol = udp
+ wait = yes
+ user = root
+ server = /usr/sbin/in.tftpd
+ server_args = -s /srv/tftpboot
+ per_source = 11
+ cps = 100 2
+ flags = IPv4
+}
+```
+
+###*10. DHCP ¼³Á¤*
+```
+sudo apt-get install isc-dhcp-server
+sudo vim /etc/dhcp/dhcpd.conf
+```
+**decpd.conf¿¡ Ãß°¡ÇÒ °Í**
+```
+#ddns-update-style none;
+
+option domain-name "yujoonote.tistory.com";
+option domain-name-servers 8.8.8.8, 8.8.6.6;
+option routers 192.168.56.1;
+option subnet-mask 255.255.255.0;
+
+default-lease-time 60;
+max-lease-time 72;
+
+allow bootp;
+allow booting;
+
+subnet 192.168.56.0 netmask 255.255.255.0 {
+ range 192.168.56.10 192.168.56.20;
+ option routers 192.168.56.1;
+ host pxe-bootos {
+ hardware ethernet 52:00:00:00:00:01;
+ filename "boot/grub/i386-pc/core.0";
+ }
+}
+```
-###*9. Å×½ºÆ®¸¦ À§ÇÑ VMÀ» ½ÇÇàÇÑ´Ù. VMµéÀÇ ³×Æ®¿öÅ© ¼³Á¤Àº DHCP·Î ÇÑ´Ù.*
+###*11. DHCP ¼¹ö Àç½ÃÀÛ*
```
-# qemu-system-i386 -m 512 -hda brdist-img.raw -net nic,macaddr=52:00:00:00:00:01 -net tap,ifname=tap1,script=no -boot n
+sudo /etc/init.d/isc-dhcp-server restart
+qemu-system-i386 -m 512 -net nic,macaddr=52:00:00:00:00:01 -net tap,ifname=tap0,script=no -boot n
```
-###*10. ½ÇÇàµÈ °¡»ó¸Ó½ÅÀº ´ÝÁö ¾ÊÀº »óÅ¿¡¼ »õ·Î¿î Å͹̳ÎÀ» »ý¼ºÇØ, ºê¸´ÁöÀÇ MAC Å×ÀÌºí¿¡ VMÀÇ ¸ÆÀÌ Æ÷ÇԵƴÂÁö È®ÀÎÇØ º¸ÀÚ.*
+###*12. tftp ÆÄÀÏ »ý¼º*
```
-# brctl showmacs br0
+# cd SecurityBootloader/
+# vim tftp
+```
+**tftp¿¡ Ãß°¡ÇÒ °Í**
+```
+#!/bin/bash
+sudo ~/g2/usr/bin/grub-mknetdir --net-directory=/srv/tftpboot --subdir=boot/grub --modules=tftp
```
+###*13. tftp ±ÇÇÑ ºÎ¿©*
+```
+# chmod a+x tftp
+# ll tftp
+# ./tftp <= grub¸¦ pxe·Î ºÎÆÃÇÒ ¼ö ÀÖµµ·Ï coreÆÄÀÏÀ» ¸¸µç´Ù. ³»ºÎÀûÀ¸·Î mkimage¸¦ ¸¸µç´Ù.
+```
-**ÀÌ Å×½ºÆ®´Â ÇϳªÀÇ VLAN¿¡¼ ÀÌ·ç¾îÁ³´Ù. VLANÀ» ÂÉ°³´Â ¹æ½ÄÀ¸·Î Multi-tenant ÀÀ¿ëÀÌ °¡´É ÇÒ°Å´Ù.**
+###*14. tftp µ¿ÀÛ È®ÀÎ*
+```
+sudo nmap localhost
+
+sudo apt-get install tftpd-hpa
+sudo service tftpd-hpa restart
+
+qemu-system-i386 -m 512 -net nic,macaddr=52:00:00:00:00:01 -net tap,ifname=tap0,script=no -boot n
+```
+
+###*ÀçºÎÆýÃ*
+```
+sudo openvpn --mktun --dev tap0
+sudo ifconfig tap0 192.168.56.1 up
+sudo /etc/init.d/isc-dhcp-server restart
+qemu-system-i386 -m 512 -net nic,macaddr=52:00:00:00:00:01 -net tap,ifname=tap0,script=no -boot n
+```
+
+