{"id":995,"date":"2013-11-12T10:44:01","date_gmt":"2013-11-12T16:44:01","guid":{"rendered":"http:\/\/www.poweradmin.com\/blog\/?p=995"},"modified":"2015-04-27T08:27:10","modified_gmt":"2015-04-27T13:27:10","slug":"pt-2-how-to-implement-dhcp-relay-agent-roas-ospf-open-shortest-path-first","status":"publish","type":"post","link":"https:\/\/www.poweradmin.com\/blog\/pt-2-how-to-implement-dhcp-relay-agent-roas-ospf-open-shortest-path-first\/","title":{"rendered":"Pt. 2-How to implement DHCP (Relay Agent), ROAS & OSPF (Open Shortest Path First)"},"content":{"rendered":"

\n\tCont'd from Part 1<\/a>\u2026<\/span><\/span>\n<\/p>\n

\n\tNow let\u2019s test other VLANs to see if computers can obtain an IP address from the server or not. This time I add another scope for Accounting VLAN (VLAN10) to the DHCP scopes and set PC1\u2019s IP configuration to automatic in Accounting VLAN. The result is shown below in Figure. 6<\/strong>.<\/span><\/span>\n<\/p>\n

\n\t\u00a0\n<\/p>\n

\n\t\"Test<\/a>\n<\/p>\n

\n\tFigure. 6<\/strong><\/span><\/span>\n<\/p>\n

\n\t\u00a0\n<\/p>\n

\n\t\"DHCP<\/a>\n<\/p>\n

\n\tFigure. 7<\/strong><\/span><\/span>\n<\/p>\n

\n\t\u00a0\n<\/p>\n

\n\tAs you can see in Figure.7<\/strong>, the DHCP request has failed because PC1 cannot access any DHCP server (in our case, Server0<\/strong>). <\/strong><\/span><\/span>\n<\/p>\n

\n\tWhat should we do to give PC1 access to the Server0\u2019s DHCP service?<\/strong><\/span><\/span>\n<\/p>\n

\n\tThe solution is very easy. You just need to add ip helper-address 192.168.100.2<\/strong> command to R1\u2019s configuration. With this command we tell the router (R1) to relay the IP request to the server in another VLAN [VLAN 100 (Server VLAN)].<\/span><\/span>\n<\/p>\n

\n\tR1>en<\/span><\/span>\n<\/p>\n

\n\tR1#config t<\/span><\/span>\n<\/p>\n

\n\tR1(config)#interface fastEthernet 0\/0.10<\/span><\/span>\n<\/p>\n

\n\tR1(config-subif)#ip helper-address 192.168.100.2<\/span><\/span>\n<\/p>\n

\n\tR1(config-subif)#exit<\/span><\/span>\n<\/p>\n

\n\tR1(config)#<\/span><\/span>\n<\/p>\n

\n\t\u00a0\n<\/p>\n

\n\tThe result of the configuration is shown below in Figure. 8. <\/strong>\u00a0<\/span><\/span>\n<\/p>\n

\n\t\"IP<\/a>\n<\/p>\n

\n\tFigure. 8<\/strong><\/span><\/span>\n<\/p>\n

\n\t\u00a0\n<\/p>\n

\n\tWe must add the ip helper-address <\/strong>command to the other VLAN\u2019s virtual interfaces on the R1 router. Performing this step, relays the DHCP requests to other PCs in the corresponding VLAN in segment A.<\/span><\/span>\n<\/p>\n

\n\tAdd other VLANs DHCP scopes to the Server0 as depicted in the following picture.<\/span><\/span>\n<\/p>\n

\n\t\"Add<\/a>\n<\/p>\n

\n\tFigure. 9<\/strong><\/span><\/span>\n<\/p>\n

\n\t\u00a0\n<\/p>\n

\n\tNow you can configure the Segment B switch yourself. Just add 2 other VLANs to the switch and name them VLAN 30 (HSE) and VLAN 40 (Logistics). Configure ROAS on R2 and test the configuration to make sure that it is working correctly.<\/span><\/span>\n<\/p>\n

\n\tImplementing OSPF for connecting 2 segments:<\/strong><\/span><\/span>\n<\/p>\n

\n\tFirst we must assign the serial 0\/0\u2019s IP addresses to both R1 and R2 routers. Issue the below commands to assign the IP addresses.<\/span><\/span>\n<\/p>\n

\n\tR1 Configuration:<\/em><\/span><\/span>\n<\/p>\n

\n\tR1>en<\/span><\/span>\n<\/p>\n

\n\tR1#config t<\/span><\/span>\n<\/p>\n

\n\tR1#interface serial 0\/0<\/span><\/span>\n<\/p>\n

\n\tR1(config-if)#ip address 192.168.1.254 255.255.255.0<\/span><\/span>\n<\/p>\n

\n\tR1(config-if)#no shutdown<\/span><\/span>\n<\/p>\n

\n\tR2 Configuration:<\/em><\/span><\/span>\n<\/p>\n

\n\tR2>en<\/span><\/span>\n<\/p>\n

\n\tR2#config t<\/span><\/span>\n<\/p>\n

\n\tR2(config)#interface serial 0\/0<\/span><\/span>\n<\/p>\n

\n\tR2(config-if)#ip address 192.168.1.253 255.255.255.0<\/span><\/span>\n<\/p>\n

\n\tR2(config-if)#no shutdown<\/span><\/span>\n<\/p>\n

\n\tR2(config-if)#clock rate 4000000<\/span><\/span>\n<\/p>\n

\n\tR2(config-if)#exit<\/span><\/span>\n<\/p>\n

\n\t\u00a0(Set Clock Rate on DCE interface. In this demonstration R2\u2019s Serial 0\/0 is DCE.)<\/span><\/span><\/span>\n<\/p>\n

\n\t\u00a0\n<\/p>\n

\n\tR1\u2019s OSPF configuration:<\/em><\/span><\/span>\n<\/p>\n

\n\tR1>en<\/span><\/span>\n<\/p>\n

\n\tR1#config t<\/span><\/span>\n<\/p>\n

\n\tR1(config)#router ospf 1<\/span><\/span>\n<\/p>\n

\n\tR1(config-router)#router-id 1.1.1.1<\/span><\/span>\n<\/p>\n

\n\tR1(config-router)#network 192.168.0.0 0.0.255.255 area 0<\/span><\/span>\n<\/p>\n

\n\tR1(config-router)#<\/span><\/span>\n<\/p>\n

\n\t00:51:07: %OSPF-5-ADJCHG: Process 1, Nbr 2.2.2.2 on Serial0\/0 from LOADING to FULL, Loading Done<\/span><\/span>\n<\/p>\n

\n\tR1(config-router)#exit<\/span><\/span>\n<\/p>\n

\n\tR1(config)#exit<\/span><\/span>\n<\/p>\n

\n\t\u00a0\n<\/p>\n

\n\tR2\u2019s OSPF configuration:<\/em><\/span><\/span>\n<\/p>\n

\n\tR2>en<\/span><\/span>\n<\/p>\n

\n\tR2#config t<\/span><\/span>\n<\/p>\n

\n\tR2(config)#router ospf 1<\/span><\/span>\n<\/p>\n

\n\tR2(config-router)#router-id 2.2.2.2<\/span><\/span>\n<\/p>\n

\n\tR2(config-router)#network 192.168.0.0 0.0.255.255 area 0<\/span><\/span>\n<\/p>\n

\n\tR2(config-router)#exit<\/span><\/span>\n<\/p>\n

\n\tR2(config)#exit<\/span><\/span>\n<\/p>\n

\n\t\u00a0\n<\/p>\n

\n\tNow both segments are set up and functional. To test the connection between the computers you need to issue the ping command. You can see the result of pinging the server in Figure.10<\/strong>.<\/span><\/span>\n<\/p>\n

\n\t\"Test<\/a>\n<\/p>\n

\n\tFigure. 10<\/strong><\/span><\/span>\n<\/p>\n

\n\t\u00a0\n<\/p>\n

\n\tTo enable the clients in segment B to obtain an IP address automatically, we need to add ip helper-address<\/strong> command to the R2 configuration on both virtual interfaces. Enter in the following commands:<\/span><\/span>\n<\/p>\n

\n\tR2\u2019s OSPF configuration:<\/em><\/span><\/span>\n<\/p>\n

\n\tR2>en<\/span><\/span>\n<\/p>\n

\n\tR2#config t<\/span><\/span>\n<\/p>\n

\n\tR2(config)#interface fastEthernet 0\/0.30<\/span><\/span>\n<\/p>\n

\n\tR2(config-subif)#ip helper-address 192.168.100.2<\/span><\/span>\n<\/p>\n

\n\tR2(config-subif)#exit<\/span><\/span>\n<\/p>\n

\n\tR2(config)#interface fastEthernet 0\/0.40<\/span><\/span>\n<\/p>\n

\n\tR2(config-subif)#ip helper-address 192.168.100.2<\/span><\/span>\n<\/p>\n

\n\tR2(config-subif)#exit<\/span><\/span>\n<\/p>\n

\n\tR2(config)#<\/span><\/span>\n<\/p>\n

\n\t\u00a0\n<\/p>\n

\n\tNow all computers on segment B should be able to obtain an IP address from the DHCP server automatically.<\/span><\/span>\n<\/p>\n

\n\tIn this article I showed you how to configure routers to implement ROAS, OSPF and DHCP relay agent in one scenario. Hope you found it useful and informative. If you have any questions, please leave them in the comments below.<\/span><\/span>\n<\/p>\n

\n\t\u2014<\/span><\/span>\n<\/p>\n

\n\tAuthor\u2019s Bio: <\/strong>Soheil has over 13 years\u2019 experience in the IT industry and is a huge fan of building websites in his spare time. He works as a Senior Technical Consultant for a company that specializes in\u00a0IT Support<\/a>\u00a0and cloud IT solutions in Australia.<\/span><\/span>\n<\/p>\n

\n\t\"Tweet<\/a>\n<\/p>\n

\n\t\"Share<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Cont’d from Part 1\u2026 Now let\u2019s test other VLANs to see if computers can obtain an IP address from the server or not. This time I add another scope for Accounting VLAN (VLAN10) to the DHCP scopes and set PC1\u2019s IP configuration to automatic in Accounting VLAN. The result is shown below in Figure. 6. […]<\/p>\n","protected":false},"author":5,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5,9,8],"tags":[],"class_list":["post-995","post","type-post","status-publish","format-standard","hentry","category-how-to","category-technical","category-windows"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.poweradmin.com\/blog\/wp-json\/wp\/v2\/posts\/995","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.poweradmin.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.poweradmin.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.poweradmin.com\/blog\/wp-json\/wp\/v2\/users\/5"}],"replies":[{"embeddable":true,"href":"https:\/\/www.poweradmin.com\/blog\/wp-json\/wp\/v2\/comments?post=995"}],"version-history":[{"count":4,"href":"https:\/\/www.poweradmin.com\/blog\/wp-json\/wp\/v2\/posts\/995\/revisions"}],"predecessor-version":[{"id":3566,"href":"https:\/\/www.poweradmin.com\/blog\/wp-json\/wp\/v2\/posts\/995\/revisions\/3566"}],"wp:attachment":[{"href":"https:\/\/www.poweradmin.com\/blog\/wp-json\/wp\/v2\/media?parent=995"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.poweradmin.com\/blog\/wp-json\/wp\/v2\/categories?post=995"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.poweradmin.com\/blog\/wp-json\/wp\/v2\/tags?post=995"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}