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DHCP Request


Dear Sir,

I am allocating IP addr with DHCP Server to my clients with 300Sec a leased time...

I understood renewal time = 50% * leased time, hence After 150 sec i am expecting request from clients to sever for renewal....

But when i captured traffic by wireshark, DHCP request interval from client is not uniform and varying between 117sec to 147sec...

Why ? What could be the reason???

Regards M Srinivasa Rao

asked 15 Apr '15, 20:09

srinu_bel's gravatar image

accept rate: 0%

One Answer:


See section 4.4.5, "Reacquisition and expiration," of RFC 2131, "Dynamic Host Configuration Protocol." Two times, T1 and T2, are defined. T1 is the renewal time. It defaults to 50% of the lease time, but the server can specify a different value.

The RFC gives two reasons why the client might try to renew its lease at times that are not exactly equal to T1:

  1. "Times T1 and T2 SHOULD be chosen with some random 'fuzz' around a fixed value, to avoid synchronization of client reacquisition."
  2. "The client MAY choose to renew or extend its lease prior to T1."

answered 15 Apr '15, 21:23

Jim%20Aragon's gravatar image

Jim Aragon
accept rate: 24%

edited 16 Apr '15, 13:41