Bug 36642
| Summary: | 4.5 man page on ipfw new option limit is way to vague. | ||
|---|---|---|---|
| Product: | Documentation | Reporter: | Joseph Barbish <barbish> |
| Component: | Books & Articles | Assignee: | freebsd-doc (Nobody) <doc> |
| Status: | Closed FIXED | ||
| Severity: | Affects Only Me | ||
| Priority: | Normal | ||
| Version: | Latest | ||
| Hardware: | Any | ||
| OS: | Any | ||
<I find this verbiage hard to comprehend what the author is trying to <say. <using this example <ipfw add allow tcp from any to me setup limit src-addr 4 <Is it saying that for each unique ip address in the src ip <address field it will allow up to 4 simultaneous connections. Look at the example in the man page: The latter can be placed on a server to make sure that a single client does not use more than 4 simultaneous connections. >So I would see >src_ip_addr 122.33.45.11 accept >src_ip_addr 122.33.45.12 accept >src_ip_addr 122.33.45.12 accept >src_ip_addr 122.33.45.11 accept >src_ip_addr 122.33.45.11 accept >src_ip_addr 122.33.45.12 accept >src_ip_addr 122.33.45.12 accept >src_ip_addr 122.33.45.11 accept >src_ip_addr 122.33.45.11 rejected >or would I see >src_ip_addr 122.33.45.11 accept >src_ip_addr 122.33.45.12 accept >src_ip_addr 122.33.45.12 accept >src_ip_addr 122.33.45.11 accept >src_ip_addr 122.33.45.11 rejected >src_ip_addr 122.33.45.12 rejected >src_ip_addr 122.33.45.12 rejected >src_ip_addr 122.33.45.11 rejected >src_ip_addr 122.33.45.11 rejected Well, according to the example in the man page, you would see what's behind door number 1. >How does Limit know when a packet has completed so as the remove it >from the count? One would assume that it uses a process similar or identical to natd. It keeps a table of active connections. >The real question is what is the limit option really doing and >how does he do it? Limit is allowing ipfw a new way to tune their networks reaction under load, and/or allowing administrators more granularity in their filtering, (e.g. We only want 4 of our techs using irc at any one time.) I don't agree that a man page should explain every little detail about it's inner workings. There are plenty of binaries that have been around for years with less documentation than this. I recommend we close this pr out. Josh State Changed From-To: open->closed This is really a question. Please ask on questions@FreeBSD.org if you are still having problems understanding the syntax. |
In FBSD version 4.5 there is a new ipfw rule option called limit. Below is the man page on this option. ******************************************************************* limit {src-addr | src-port | dst-addr | dst-port} N The firewall will only allow N connections with the same set of parameters as specified in the rule. One or more of source and destination addresses and ports can be specified. To limit the number of connections a user can open you can use the following type of rules: ipfw add allow tcp from my-net/24 to any setup limit src-addr 10 ipfw add allow tcp from any to me setup limit src-addr 4 The former (assuming it runs on a gateway) will allow each host on a /24 network to open at most 10 TCP connections. The latter can be placed on a server to make sure that a single client does not use more than 4 simultaneous connections. ******************************************************************* I find this verbiage hard to comprehend what the author is trying to say. using this example ipfw add allow tcp from any to me setup limit src-addr 4 Is it saying that for each unique ip address in the src ip address field it will allow up to 4 simultaneous connections. So I would see src_ip_addr 122.33.45.11 accept src_ip_addr 122.33.45.12 accept src_ip_addr 122.33.45.12 accept src_ip_addr 122.33.45.11 accept src_ip_addr 122.33.45.11 accept src_ip_addr 122.33.45.12 accept src_ip_addr 122.33.45.12 accept src_ip_addr 122.33.45.11 accept src_ip_addr 122.33.45.11 rejected or would I see src_ip_addr 122.33.45.11 accept src_ip_addr 122.33.45.12 accept src_ip_addr 122.33.45.12 accept src_ip_addr 122.33.45.11 accept src_ip_addr 122.33.45.11 rejected src_ip_addr 122.33.45.12 rejected src_ip_addr 122.33.45.12 rejected src_ip_addr 122.33.45.11 rejected src_ip_addr 122.33.45.11 rejected How does Limit know when a packet has completed so as the remove it from the count? The real question is what is the limit option really doing and how does he do it? Fix: Send me a detailed explanation that I can use to suggest some verbiage to add to clarify how the limit option functions.