Hi,

I’ve already posted this to the user’s mailing list, but I think that here is a best place for this.

I’ve noticed that rlm_ippool is nearly always reassigning an IP address that has just been releasing for a new connexion. This causes some TCP connexion problems because of the TIME_WAIT state.

Scenario:

1/ one device connects using source port 1024 (ppp) and gets an IP address from freeradius

2/ this device disconnects, the ip is freed from the pool

3/ another devices connects using source port 1024 and gets the same ip address as before

4/ the connexion is impossible to the server because the connexion of last device is still in TIME_WAIT state

How can I make sure an IP address is not assigned before some time period (240 seconds, time period of the TIME_WAIT state) after being released?

I got one answer :

>Interesting.

>The IPs are allocated by a GDBM walk of the database, and use of the first free or expired IP. This will always tend to be the same one hence the repeat >allocations.

>It would in theory be possible to save the key from the last walk, and next time we allocate an IP start from that key and wrap back around, which would >allocate IPs in a more round-robin fashion.

I would appreciate if someone can help doing the hack or give me some hints to modify rlm_ippool.c to add some retention time parameter to make sure an ip is not reassigned instantly after being freed or to make things work more in a random or round robin way.

Thanks in advance.

Regards,

Sebastien.