Too many open files error

[Éric Allard]

We often get a lot of "ns_resp:TCP truncated:" in our log until we get
a "Too many open files". When we obtain this "Too many open files",
the server doesn't answer for a while. I know that happen when we got
an answer that was too large to fit into a DNS/TCP answer but I don't
know how I can provide my server from this problem!
Here my fd configuration on Solaris 8 in my /etc/system

* file descriptor
set rlim_fd_cur=2048
set rlim_fd_max=4096

Here a sample of my log file (/var/log/namedlog)

Mar 13 12:03:03 alexis named[3532]: [ID 295310 local0.error] ns_resp:
TCP truncated:
"42.220.218.216.in-addr.arpa" IN PTR from [216.218.220.42].53
Mar 13 12:03:03 alexis last message repeated 1 time
Mar 13 12:03:03 alexis named[3532]: [ID 295310 local0.notice] fcntl(fd,
F_DUPFD, 20)
: Too many open files
Mar 13 12:03:03 alexis named[3532]: [ID 295310 local0.error] ns_resp:
TCP truncated:
"42.220.218.216.in-addr.arpa" IN PTR from [216.218.220.42].53
Mar 13 12:03:04 alexis named[3532]: [ID 295310 local0.notice] fcntl(fd,
F_DUPFD, 20)
: Too many open files

Any hints will be gracefull!
Thanks!