IP Helper

[jongclee02]

How many IP Helper (DHCP IP address) can I have on CISCO 2800 and 3800 series routers?

[Charles Hill]

According to a couple of postings, it is 16 per interface/vlan. 

http://www.gossamer-threads.com/lists/cisco/nsp/63394

https://supportforums.cisco.com/discussion/11458236/maximun-number-ip-helper-address

I'll verify this tomorrow morning on a 3800 series router, if no one else confirms this.

Hope this helps,

Please rate helpful postings.

Thanks.

[Reza Sharifi]

I don't know if there is a limit.  I configured 32 on a 3845 and I could still do even more.

How may DHCP servers do you have?

HTH

[Charles Hill]

Hey Reza,

Was that 32 total or per interface that was configured?

[Reza Sharifi]

Hi Charles,

I configured 32 different IP helper addresses under one interface and could do even more.

HTH

[Charles Hill]

Thank you Reza,

(+5) to Reza

I just verified on a 3925 and added 50 ip helper addresses and could have kept going.  Wow!

 CISCO3925

interface GigabitEthernet0/1
 no ip address
 ip helper-address 10.1.1.1
 ip helper-address 10.1.1.2
 ip helper-address 10.1.1.3
 ip helper-address 10.1.1.4
 ip helper-address 10.1.1.5
 ip helper-address 10.1.1.6
 ip helper-address 10.1.1.7
 ip helper-address 10.1.1.8
 ip helper-address 10.1.1.9
 ip helper-address 10.1.1.10
 ip helper-address 10.1.1.11
 ip helper-address 10.1.1.12
 ip helper-address 10.1.1.13
 ip helper-address 10.1.1.14
 ip helper-address 10.1.1.15
 ip helper-address 10.1.1.16
 ip helper-address 10.1.1.17
 ip helper-address 10.1.1.18
 ip helper-address 10.1.1.19
 ip helper-address 10.1.1.20
 ip helper-address 10.1.1.21
 ip helper-address 10.1.1.22
 ip helper-address 10.1.1.23
 ip helper-address 10.1.1.24
 ip helper-address 10.1.1.25
 ip helper-address 10.1.1.26
 ip helper-address 10.1.1.27
 ip helper-address 10.1.1.28
 ip helper-address 10.1.1.29
 ip helper-address 10.1.1.30
 ip helper-address 10.1.1.31
 ip helper-address 10.1.1.32
 ip helper-address 10.1.1.33
 ip helper-address 10.1.1.34
 ip helper-address 10.1.1.35
 ip helper-address 10.1.1.36
 ip helper-address 10.1.1.37
 ip helper-address 10.1.1.38
 ip helper-address 10.1.1.39
 ip helper-address 10.1.1.40
 ip helper-address 10.1.1.41
 ip helper-address 10.1.1.42
 ip helper-address 10.1.1.43
 ip helper-address 10.1.1.44
 ip helper-address 10.1.1.45
 ip helper-address 10.1.1.46
 ip helper-address 10.1.1.47
 ip helper-address 10.1.1.48
 ip helper-address 10.1.1.49
 ip helper-address 10.1.1.50
 shutdown
 duplex auto
 speed auto
end