DHCP on ISA550 Stops Giving IP Addresses

[txlombardi_2]

I have a serious problem at a new ISA550 installation.  The client does not have a server, so they are forced to use the ISA550's DHCP and it doesn't work.  It simply stops giving out IP addresses even though there are plenty to be given out.  The facility uses mostly wireless access points with a mix of laptop, hand held devices, and desktops.  It doesn't make a difference if the client is wireless or plugged in.  For no apparent reason, they don't get an IP address until the device is restarted.  The rub here is the ISA550 replaced a home router with my guarantee that they would not have to restart it to get it to work, and now that is not the case.  Another problem is the ISA550 will not permit more than a 1 day DHCP lease, which is simply unacceptable.  The device has the latest firmware, 1.2.17, so updating to see if it corrects the problem is not an option.

Can anyone tell me what is going on and how to fix it before the client rips it out of their rack?                  

[SHAWN EFTINK]

I do agree that the 1 day lease max is a hassle considering that 8 is a pretty common standard.

A few questions:

1. Roughly how many devices are on the network using DHCP?
   
2. Are you seeing any erros on the ISA leading you to believe the DHCP issue is at the ISA?
   
3. What type(s) of APs are you using?
   
4. When you say it doesn't matter if the user is wireless or plugged in, are the plugged in users directly connected to the ISA or an interim switch?
   
5. What type(s) of switches are you using?
   
   • Are the switches managed or unmanaged?
     
6. Are all the users on the Default VLAN of the ISA or do you have different VLANs for different users setup?
   

Shawn Eftink
CCNA/CCDA

Please rate all helpful posts and mark correct answers to assist others searching for solutions in the community.

[txlombardi_2]

1. Roughly how many devices are on the network using DHCP?
   About 25
   
2. Are you seeing any erros on the ISA leading you to believe the DHCP issue is at the ISA?
   Log is enabled but nothing in the log.  That's my next post.
   
3. What type(s) of APs are you using?
   They have UniFi-Pro access points installed.  The DHCP problem happens with cabled connections, too.  I am on my way this afternoon to install a Cisco SG200-26 switch.  They have Intellinet now.
   
4. When you say it doesn't matter if the user is wireless or plugged in, are the plugged in users directly connected to the ISA or an interim switch?
   They are connected to the Intellinet switch.
   
5. What type(s) of switches are you using?
   
   • Are the switches managed or unmanaged?
     Intellinet - unmanaged
     
6. Are all the users on the Default VLAN of the ISA or do you have different VLANs for different users setup?
   All users on Default VLAN
   

[SHAWN EFTINK]

Anthony,

It looks like you're on the right track.  I too would recommend swapping out the Unmanaged Intellinet switch for a Managed Cisco switch to narrow down the issue to cabled users and see if that remedies their problem.  I'm also assuming the APs are all connected to that Intellnet switch, so hopefully that will be the culprit and fixed with the replacement switch.  At least having a managed switch will allow for additional troubleshooting.

With you not having any erros in the logs, and the fact that you replaced another device that was requiring a reboot every night, I'm inclined to believe the issue isn't the ISA.  It could be something as simple as a duplex mismatch, issues with that switch, etc.  Either way, please let us know the results of your troubleshooting.  Thank you.

Shawn Eftink
CCNA/CCDA

Please rate all helpful posts and mark correct answers to assist others searching for solutions in the community.

[txlombardi_2]

This is a report back on the status of this issue.  Since I replaced the Intellinet gigabit switch with a Cisco SG200-26, a recurrence of the appliance not giving out DHCP addresses has not recurred.  If there is a change, I will post back.

Cisco - You really need to permit longer DHCP lease times than one day.  That is just wrong.

[SHAWN EFTINK]

Anthony,
Thanks for taking the time to post an update. I'm thrilled to hear that it seems to be running better.

Sent from Cisco Technical Support iPhone App

[SHAWN EFTINK]

Anthony,
Everything still running good? Can we consider this issue closed and mark a correct answer if so?

Sent from Cisco Technical Support iPhone App

[txlombardi_2]

I emailed the client and asked if they have had any further problems, but they have not replied.  Let's go on the premise that if there was still a problem they would let me know and say the matter is closed.

Cisco - I'm still not happy that I can't get more than a one day lease on DHCP address leases.  You really need to change that or at least impart the logic of this restriction.