So from what I understand EIGRP works on top of the IP protocol layer 3 and uses RTP to multicast address 224.0.010 on PORT 88

But Kerberos also uses UDP PORT 88 for authentication.

So would there be any network traffic conflict here? Why not?

(Apologies for my vague knowledge, I am not a network guy and just studying at present.)

  • omg misread withdrawing question my bad
    – Sam Wheel
    Jun 3, 2021 at 14:20

2 Answers 2


That is incorrect. EIGRP uses IP protocol number 88. It doesn't use UDP at all.

For reference, UDP uses IP protocol number 17


You're confusing Layer4 ports with Layer3 protocol numbers. RTP in this case runs on Layer3 and has nothing to do with the RTP that is used in VoIP technologies. RTP is used for basic sequence/acknowledge mechanism (similar to the one in TCP) that is delivered via unreliable IP transport. There are is no Layer4 or upper layer protocols running on top of the IP header and the IP protocol number will be 88 (which is EIGRP)

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