I'm using a 3300 to load-balance three ADSL connections (each via a 2820). This services a LAN with around 100 users.
Periodically, the 3300 grinds to a halt, at which point it responds very slowly to pings (1700-2000ms when plugged directly into one of its LAN ports). All traffic through the router slows down.
An odd symptom is found in the NAT table. When the router has been up for a few hours, the level of active NAT sessions hovers at around 4,000. I have never seen it rise above 4,100 and it is almost always between 4,050 and 4,100. I can't account for this since we have no bandwidth- or session-limiting features switched on.
This is the second 3300 we've installed in this role. The first 3300 exhibited the same behaviour. The configuration was copied from the old router to the new router (not my doing!) so it is conceivable that some rogue setting was copied across. I have however trawled through the config with a fine-tooth comb and have not been able to find any obvious reason for this behaviour.
I'm most baffled by the apparent limit on NAT sessions, since everything I've read about this router suggests it should easily be able to handle 50k+. But perhaps that's a red herring.
Firmware: Vigor3300V+ series 2.6.3 (EN) this is the latest firmware, I believe
WAN1 is running at about 8Mbps
WAN2 likewise
WAN3 is running at about 22Mbps
I am load-balancing the three WANs in the following ratio: 20:20:60.
MTU on all three WANs is set to 1500 (default)
Incoming VPNs pass through to a RRAS server.
Port forwarding rules are in place on all WANs - nothing unusual about them.
A couple of possibly significant entries in the config:
session_general=0,1000
session_limit_size=0
A soft reboot returns the router to normal operation and it can be days or weeks before the problem occurs again. Can anyone shed any light on this?
Honest news, reviews and how-tos: Geek & Dummy | http://geekanddummy.com
