I am seeing some strange things on my 2950 switch regarding arps. Two questions:
1) Why do some arp entries always show an age of 0 mins.?
2) Why do some arp entries have a hypen (-) in the age column?
3) Look at the sh arp output below and the arp debug to follow. Why do the arp debugs not show up in the "sh arp" output, just certain address? Shouldn't any arp request show up in the arp cache?
2950-24# sh arp
Protocol Address Age (min) Hardware Addr Type Interfa
Internet 10.0.0.2 - 0009.43a0.ae80 ARPA VLAN1
Internet 10.0.0.7 0 0090.2789.5609 ARPA VLAN1
Internet 10.0.0.4 0 0090.27e0.6714 ARPA VLAN1
Log Buffer (4096 bytes):
51:03.914: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.170 VLAN1
*Apr 2 21:51:04.922: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.1
70 VLAN1
*Apr 2 21:51:04.922: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.1
70 VLAN1
*Apr 2 21:51:05.926: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.1
70 VLAN1
*Apr 2 21:51:12.942: IP ARP: rcvd req src 10.0.0.13 00b0.d0d1.de67, dst 10.0.0.
15 VLAN1
*Apr 2 21:51:22.058: IP ARP: rcvd req src 10.0.0.13 00b0.d0d1.de67, dst 10.0.0.
16 VLAN1
*Apr 2 21:51:25.622: IP ARP: rcvd req src 10.0.0.172 000f.1fb4.8325, dst 10.0.0
.15 VLAN1
*Apr 2 21:51:26.934: IP ARP: rcvd req src 10.0.0.150 0090.27e0.4372, dst 10.0.0
.15 VLAN1
*Apr 2 21:51:39.986: IP ARP: rcvd req src 10.0.0.4 0090.27e0.6714, dst 10.0.0.1
VLAN1
*Apr 2 21:51:51.574: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.1
5 VLAN1
*Apr 2 21:51:57.882: IP ARP: rcvd req src 10.0.0.154 00d0.b74c.3a9b, dst 10.0.0
.15 VLAN1
*Apr 2 21:52:15.670: IP ARP: rcvd req src 10.0.0.172 000f.1fb4.8325, dst 10.0.0
Log Buffer (4096 bytes):
51:03.914: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.170 VLAN1
*Apr 2 21:51:04.922: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.1
70 VLAN1
*Apr 2 21:51:04.922: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.1
70 VLAN1
*Apr 2 21:51:05.926: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.1
70 VLAN1
*Apr 2 21:51:12.942: IP ARP: rcvd req src 10.0.0.13 00b0.d0d1.de67, dst 10.0.0.
15 VLAN1
*Apr 2 21:51:22.058: IP ARP: rcvd req src 10.0.0.13 00b0.d0d1.de67, dst 10.0.0.
16 VLAN1
*Apr 2 21:51:25.622: IP ARP: rcvd req src 10.0.0.172 000f.1fb4.8325, dst 10.0.0
.15 VLAN1
*Apr 2 21:51:26.934: IP ARP: rcvd req src 10.0.0.150 0090.27e0.4372, dst 10.0.0
.15 VLAN1
*Apr 2 21:51:39.986: IP ARP: rcvd req src 10.0.0.4 0090.27e0.6714, dst 10.0.0.1
VLAN1
*Apr 2 21:51:51.574: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.1
5 VLAN1
*Apr 2 21:51:57.882: IP ARP: rcvd req src 10.0.0.154 00d0.b74c.3a9b, dst 10.0.0
.15 VLAN1
*Apr 2 21:52:15.670: IP ARP: rcvd req src 10.0.0.172 000f.1fb4.8325, dst 10.0.0
*Apr 2 21:54:02.442: IP ARP: rcvd req src 10.0.0.55 00d0.b74c.38e9, dst 10.0.0.
13 VLAN1
*Apr 2 21:54:05.414: IP ARP: rcvd req src 10.0.0.7 0090.2789.5609, dst 10.0.0.2
VLAN1
*Apr 2 21:54:05.414: IP ARP: sent rep src 10.0.0.2 0009.43a0.ae80,
dst 10.0.0.7 0090.2789.5609 VLAN1
*Apr 2 21:54:15.770: IP ARP: rcvd req src 10.0.0.16 00b0.d0f9.4d72, dst 10.0.0.
15 VLAN1
*Apr 2 21:54:15.790: IP ARP: rcvd req src 10.0.0.7 0090.2789.5609, dst 10.0.0.1
72 VLAN1
*Apr 2 21:54:16.318: IP ARP: rcvd req src 10.0.0.55 00d0.b74c.38e9, dst 10.0.0.
18 VLAN1
*Apr 2 21:54:18.430: IP ARP: rcvd req src 10.0.0.7 0090.2789.5609, dst 10.0.0.7
4 VLAN1
*Apr 2 21:54:19.866: IP ARP: rcvd req src 10.0.0.9 0090.27dc.9f41, dst 10.0.0.1
5 VLAN1
*Apr 2 21:54:30.702: IP ARP: rcvd req src 10.0.0.8 00b0.d0d1.de55, dst 10.0.0.1
7 VLAN1
*Apr 2 21:54:36.630: IP ARP: rcvd req src 10.0.0.18 0010.5a00.eaf7, dst 10.0.0.
15 VLAN1
*Apr 2 21:54:40.474: IP ARP: rcvd req src 10.0.0.4 0090.27e0.6714, dst 10.0.0.2
0 VLAN1
*Apr 2 21:54:43.486: IP ARP: rcvd req src 10.0.0.32 0001.294b.9b3f, dst 10.0.0.
33 VLAN1
1) Why do some arp entries always show an age of 0 mins.?
2) Why do some arp entries have a hypen (-) in the age column?
3) Look at the sh arp output below and the arp debug to follow. Why do the arp debugs not show up in the "sh arp" output, just certain address? Shouldn't any arp request show up in the arp cache?
2950-24# sh arp
Protocol Address Age (min) Hardware Addr Type Interfa
Internet 10.0.0.2 - 0009.43a0.ae80 ARPA VLAN1
Internet 10.0.0.7 0 0090.2789.5609 ARPA VLAN1
Internet 10.0.0.4 0 0090.27e0.6714 ARPA VLAN1
Log Buffer (4096 bytes):
51:03.914: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.170 VLAN1
*Apr 2 21:51:04.922: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.1
70 VLAN1
*Apr 2 21:51:04.922: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.1
70 VLAN1
*Apr 2 21:51:05.926: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.1
70 VLAN1
*Apr 2 21:51:12.942: IP ARP: rcvd req src 10.0.0.13 00b0.d0d1.de67, dst 10.0.0.
15 VLAN1
*Apr 2 21:51:22.058: IP ARP: rcvd req src 10.0.0.13 00b0.d0d1.de67, dst 10.0.0.
16 VLAN1
*Apr 2 21:51:25.622: IP ARP: rcvd req src 10.0.0.172 000f.1fb4.8325, dst 10.0.0
.15 VLAN1
*Apr 2 21:51:26.934: IP ARP: rcvd req src 10.0.0.150 0090.27e0.4372, dst 10.0.0
.15 VLAN1
*Apr 2 21:51:39.986: IP ARP: rcvd req src 10.0.0.4 0090.27e0.6714, dst 10.0.0.1
VLAN1
*Apr 2 21:51:51.574: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.1
5 VLAN1
*Apr 2 21:51:57.882: IP ARP: rcvd req src 10.0.0.154 00d0.b74c.3a9b, dst 10.0.0
.15 VLAN1
*Apr 2 21:52:15.670: IP ARP: rcvd req src 10.0.0.172 000f.1fb4.8325, dst 10.0.0
Log Buffer (4096 bytes):
51:03.914: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.170 VLAN1
*Apr 2 21:51:04.922: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.1
70 VLAN1
*Apr 2 21:51:04.922: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.1
70 VLAN1
*Apr 2 21:51:05.926: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.1
70 VLAN1
*Apr 2 21:51:12.942: IP ARP: rcvd req src 10.0.0.13 00b0.d0d1.de67, dst 10.0.0.
15 VLAN1
*Apr 2 21:51:22.058: IP ARP: rcvd req src 10.0.0.13 00b0.d0d1.de67, dst 10.0.0.
16 VLAN1
*Apr 2 21:51:25.622: IP ARP: rcvd req src 10.0.0.172 000f.1fb4.8325, dst 10.0.0
.15 VLAN1
*Apr 2 21:51:26.934: IP ARP: rcvd req src 10.0.0.150 0090.27e0.4372, dst 10.0.0
.15 VLAN1
*Apr 2 21:51:39.986: IP ARP: rcvd req src 10.0.0.4 0090.27e0.6714, dst 10.0.0.1
VLAN1
*Apr 2 21:51:51.574: IP ARP: rcvd req src 10.0.0.5 00b0.d0fe.8b5a, dst 10.0.0.1
5 VLAN1
*Apr 2 21:51:57.882: IP ARP: rcvd req src 10.0.0.154 00d0.b74c.3a9b, dst 10.0.0
.15 VLAN1
*Apr 2 21:52:15.670: IP ARP: rcvd req src 10.0.0.172 000f.1fb4.8325, dst 10.0.0
*Apr 2 21:54:02.442: IP ARP: rcvd req src 10.0.0.55 00d0.b74c.38e9, dst 10.0.0.
13 VLAN1
*Apr 2 21:54:05.414: IP ARP: rcvd req src 10.0.0.7 0090.2789.5609, dst 10.0.0.2
VLAN1
*Apr 2 21:54:05.414: IP ARP: sent rep src 10.0.0.2 0009.43a0.ae80,
dst 10.0.0.7 0090.2789.5609 VLAN1
*Apr 2 21:54:15.770: IP ARP: rcvd req src 10.0.0.16 00b0.d0f9.4d72, dst 10.0.0.
15 VLAN1
*Apr 2 21:54:15.790: IP ARP: rcvd req src 10.0.0.7 0090.2789.5609, dst 10.0.0.1
72 VLAN1
*Apr 2 21:54:16.318: IP ARP: rcvd req src 10.0.0.55 00d0.b74c.38e9, dst 10.0.0.
18 VLAN1
*Apr 2 21:54:18.430: IP ARP: rcvd req src 10.0.0.7 0090.2789.5609, dst 10.0.0.7
4 VLAN1
*Apr 2 21:54:19.866: IP ARP: rcvd req src 10.0.0.9 0090.27dc.9f41, dst 10.0.0.1
5 VLAN1
*Apr 2 21:54:30.702: IP ARP: rcvd req src 10.0.0.8 00b0.d0d1.de55, dst 10.0.0.1
7 VLAN1
*Apr 2 21:54:36.630: IP ARP: rcvd req src 10.0.0.18 0010.5a00.eaf7, dst 10.0.0.
15 VLAN1
*Apr 2 21:54:40.474: IP ARP: rcvd req src 10.0.0.4 0090.27e0.6714, dst 10.0.0.2
0 VLAN1
*Apr 2 21:54:43.486: IP ARP: rcvd req src 10.0.0.32 0001.294b.9b3f, dst 10.0.0.
33 VLAN1