Limits and timeouts



There are various specific timeouts and limits applicable to the FireBrick operation. These are not specified within the text of the rechnical reference manual, but collected together in this one appendix.
 
Ethernet
Total MAC cache size 2048
Ethernet MTU 1500 bytes
ARP
Cache size per interface 256
Time from initial request to first repeat 1.00 to 3.56 seconds
Repeat request time 2.56 seconds
Timeout for ARP request 10 seconds
Hold time before refresh 60 seconds
Max packets pending ARP reply 20
ARP max outstanding sessions 10
ARP session timeout 2 seconds
ARP session hold after reply 0.1 seconds
Session tracking
Max sessions 4000
Default TCP initial timeout 10 seconds
Default TCP ongoing timeout 2 hours
TCP timeout after RST received either way 5 seconds
TCP timeout after ACK after FIN each way 5 seconds
TCP timeout after ICMP error 5 seconds
Default UDP initial timeout 60 seconds
Default UDP ongoing timeout 10 seconds
UDP timeout after ICMP error 10 seconds
Default ICMP initial timeout 10 seconds
Default ICMP ongoing timeout 2 seconds
ICMP timeout after ICMP error 10 seconds
Default other initial timeout 100 seconds
Default other ongoing timeout 100 minutes
Profiles
Normal ping interval 10 seconds
Repeat ping interval on no response 0.869 seconds
Repeat ping attempts on no response 7
Max loss of host detect time 16 seconds
Min loss of host detect time 6 seconds
Average loss of host detect time 11 seconds
Max acquire of host detect time 10 seconds + ping response time
Min acquire of host detect time 0 seconds + ping response time
Average acquire host detect time 5 seconds + ping response time
DHCP
Max DHCP expiry 7 days
Default renewal Half expiry
Default expiry 2 hours
Max allocations 256 per interface
Logged client name length 20 characters
Time
Clock refresh time 55 to 56 minutes
Clock request interval 10 seconds
Clock request abandon 2 minutes