proxy arp

In the above diagram , both hosts don't have default routes. But both are in the same /16 subnet. When host1 tries to ping host2 will it be able to ping ? Yes this behaviour due to the Proxy Arp feature.
Note: Cisco by default enabled the proxy arp feature you have to disable it manually .

Check the following Debug messages "debug arp" from the router.
When the Arp request for 192.168.20.101 received on the router Fa0/1 it replies with its own mac address of fa0/1. (c200.03fc.0001)and vice versa

*Mar 1 00:11:43.071: IP ARP: rcvd req src 192.168.12.154 00aa.00f4.6800, dst 192.168.20.101 FastEthernet0/1
*Mar 1 00:11:43.075: IP ARP: sent rep src 192.168.20.101 c200.03fc.0001,dst 192.168.12.154 00aa.00f4.6800 FastEthernet0/1

*Mar 1 00:13:13.067: IP ARP: rcvd req src 192.168.20.101 00aa.0041.1d00, dst 192.168.12.154 FastEthernet0/0
*Mar 1 00:13:13.067: IP ARP: sent rep src 192.168.12.154 c200.03fc.0000,
dst 192.168.20.101 00aa.0041.1d00 FastEthernet0/0


following command per interface can disable the proxy arp feature.
# no ip proxy-arp.



Comments

Post a Comment

Popular posts from this blog

l2tpv3 configuration reference

Image
Reference Comparing , Designing and Deploying VPNs chap - 02 : L2TPv3 is the enhanced version of L2TPv2 protocol. Mikrotik uses L2TPv2 i suppose but it offer another similar tunneling mechanism as EOIP. L2TPv3 in cisco provides Pseudo-wire services to the customer. L2TPv3 only require the IP connectivity between peers but it can transport Ethernet, 802.1Q , HDLC, PPP framerelay etc. Advantage over MPLS is the customer having the full control of their routing domain. L2TP depolyment methods having 3 topologies LAC - LNS , LNS - LNS , LAC - LAC Following Diagram explain simple LAC - LAC L2TPv3 setup. It uses two types of messages: control connection messages - used for signaling between LCEs session data messages - Used to transport layer 2 protocols and connections Data channel Message Header having Session ID & cookie to correctly associate with the tunnel Deploying dynamic Pseudowires session 1) configure CEF - Its default in IOSs now. 2) configure a loopback in
Read more

PPTP Server as Cisco for Mikrotik Client

Image
Following configuration explains the Cisco as PPTP server and connecting two sites: Following Configuration needed to enable the VPDN and default server: vpdn enable ! vpdn-group Mtik ! Default PPTP VPDN group accept-dialin protocol pptp virtual-template 1 interface Virtual-Template1 ip unnumbered Loopback0 peer default ip address pool IPPOOL1 ppp encrypt mppe auto required ppp authentication ms-chap-v2 ms-chap pap ip local pool IPPOOL1 192.168.150.10 192.168.150.224 Few more additional things we need to keep the same ip address for the user: aaa new-model ! ! aaa authentication ppp default local aaa authorization network default local ! aaa attribute list Gobi attribute type addr 192.168.150.13 service ppp protocol ip mandatory attribute type route "10.0.0.0 255.255.255.0 192.168.150.13" attribute type interface-config "description Gobi-test" Finally apply the attribute list to the user: username gobi password 0 test username gobi aaa attri
Read more