IP Protocol Numbers
When IP encapsulates another protoctol it labels the protoctol field with a number to define the next layer.
| IP Protocol Number | Description |
|---|---|
| 1 | ICMP |
| 2 | IGMP |
| 6 | TCP |
| 17 | UDP |
| 46 | RSVP |
| 47 | GRE |
| 51 | ESP (IPSec) |
| 51 | AH (IPSec) |
| 69 | TFTP |
| 88 | EIGRP |
| 89 | OSPF |
| 103 | PIM |
| 112 | VRRP |
| 115 | L2TP |
| 161 | SNMP |
| 162 | TRAPS |
Cisco Administrative Distance
| Protocol | Administrative Distance |
|---|---|
| Connected | 0 |
| Static | 1 |
| EIGRP Summary | 5 |
| eBGP | 20 |
| EIGRP Internal | 90 |
| OSPF | 110 |
| IS-IS | 115 |
| RIP | 120 |
| ODR | 160 |
| EIGRP External | 170 |
| iBGP | 200 |
| Unknown/Infinite1 | 255 |
Troubleshooting TechNotes - What is Administrative Distance? - Cisco
1
Can use to do route-filtering.