<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML ><HEAD ><TITLE >Frequently Asked Questions</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK REL="HOME" TITLE="Linux IP Masquerade HOWTO" HREF="index.html"><LINK REL="PREVIOUS" TITLE="Gamers: The LooseUDP patch" HREF="looseudp.html"><LINK REL="NEXT" TITLE="( Distro ) - What Linux Distributions support IP Masquerading?" HREF="masq-supported-distributions.html"></HEAD ><BODY CLASS="CHAPTER" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >Linux IP Masquerade HOWTO</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="looseudp.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="masq-supported-distributions.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="CHAPTER" ><H1 ><A NAME="FAQ" ></A >Chapter 7. Frequently Asked Questions</H1 ><DIV CLASS="TOC" ><DL ><DT ><B >Table of Contents</B ></DT ><DT >7.1. <A HREF="masq-supported-distributions.html" >( Distro ) - What Linux Distributions support IP Masquerading?</A ></DT ><DT >7.2. <A HREF="faq-hardware.html" >( Requirements ) - What are the minimum hardware requirements and any limitations for IP Masquerade? How well does it perform?</A ></DT ><DT >7.3. <A HREF="faq-command-not-found.html" >( Errors ) - When I run my specific rc.firewall-* ruleset, I get "command not found" errors. Why?</A ></DT ><DT >7.4. <A HREF="still-wont-work.html" >( Still wont work ) - I've checked all my configurations, I still can't get IP Masquerade to work. What should I do?</A ></DT ><DT >7.5. <A HREF="masq-list.html" >( Email list ) - How do I join or view the IP Masquerade and/or IP Masqurade Developers mailing lists and archives?</A ></DT ><DT >7.6. <A HREF="what-is-masq.html" >( NAT vs. Proxy ) - How does IP Masquerade differ from Proxy or NAT services?</A ></DT ><DT >7.7. <A HREF="gui-tools.html" >( GUI ) - Are there any GUI firewall creation/management tools?</A ></DT ><DT >7.8. <A HREF="masq-and-dyn-addr.html" >( MASQ and Dynamic IPs ) - Does IP Masquerade work with dynamically assigned IP addresses?</A ></DT ><DT >7.9. <A HREF="diff-network-support.html" >( MASQ and various networks ) - Can I use a cable modem (both bi-directional and with modem returns), DSL, satellite link, etc. to connect to the Internet and use IP Masquerade?</A ></DT ><DT >7.10. <A HREF="masq-and-dod.html" >( Dial on Demand ) - Can I use Diald or the Dial-on-Demand feature of PPPd with IP MASQ?</A ></DT ><DT >7.11. <A HREF="masq-supported-apps.html" >( Apps ) - What applications are supported with IP Masquerade?</A ></DT ><DT >7.12. <A HREF="distro-specific.html" >( Distro Setup ) - How can I get IP Masquerade running on Redhat, Debian, Slackware, etc.?</A ></DT ><DT >7.13. <A HREF="masq-timeouts.html" >( Timeouts ) - Connections seem to break if I don't use them often. Why is that?</A ></DT ><DT >7.14. <A HREF="masq-behavior.html" >( Odd Behavior ) - When my Internet connection first comes up, nothing works. If I try again, everything then works fine. Why is this?</A ></DT ><DT >7.15. <A HREF="mtu-issues.html" >( MTU ) - IP MASQ seems to be working fine but some sites don't work. This usually happens with WWW and some FTP sites.</A ></DT ><DD ><DL ><DT >7.15.1. <A HREF="mtu-issues.html#AEN2620" >Enabling PMTU Clamping for PPPoE and some PPP Users:</A ></DT ><DT >7.15.2. <A HREF="mtu-issues.html#AEN2628" >Clamping the MSS via IPTABLES:</A ></DT ><DT >7.15.3. <A HREF="mtu-issues.html#AEN2633" >Changing the External MTU of the MASQ server:</A ></DT ><DT >7.15.4. <A HREF="mtu-issues.html#AEN2647" >Changing the MTU of various operating systems:</A ></DT ><DD ><DL ><DT >7.15.4.1. <A HREF="mtu-issues.html#AEN2656" >Changing the MTU on Linux:</A ></DT ><DT >7.15.4.2. <A HREF="mtu-issues.html#AEN2660" >Changing the MTU on MS Windows 2000</A ></DT ><DT >7.15.4.3. <A HREF="mtu-issues.html#AEN2664" >Changing the MTU on MS Windows NT 4.x</A ></DT ><DT >7.15.4.4. <A HREF="mtu-issues.html#AEN2668" >Changing the MTU on MS Windows 98:</A ></DT ><DT >7.15.4.5. <A HREF="mtu-issues.html#AEN2672" >Changing the MTU on MS Windows 95:</A ></DT ></DL ></DD ></DL ></DD ><DT >7.16. <A HREF="masqed-ftp.html" >( FTP ) - MASQed FTP clients don't work.</A ></DT ><DT >7.17. <A HREF="masq-performace.html" >( Performance ) - IP Masquerading seems slow</A ></DT ><DT >7.18. <A HREF="portfw-issues.html" >( PORTFW ) - IP Masquerading with PORTFWing seems to break when my line is idle for long periods</A ></DT ><DT >7.19. <A HREF="portfw-local.html" >( PORTFW - Locally ) - I can't reach my PORTFWed server from the INTERNAL lan</A ></DT ><DT >7.20. <A HREF="masq-logs.html" >( Logs ) - Now that I have IP Masquerading up, I'm getting all sorts of weird notices and errors in the SYSLOG log files. How do I read the IPTABLES/IPCHAINS/IPFWADM firewall errors?</A ></DT ><DT >7.21. <A HREF="reducing-masq-logs.html" >( Log Reduction ) - My logs are filling up with packet hits due to the new "stronger" rulesets. How can I fix this?</A ></DT ><DT >7.22. <A HREF="masq-host-security.html" >( MASQ Security ) - Can I configure IP MASQ to allow Internet users to directly contact internal MASQed servers?</A ></DT ><DT >7.23. <A HREF="no-free-ports.html" >( Free Ports ) - I'm getting "kernel: ip_masq_new(proto=UDP): no free ports." in my SYSLOG files. Whats up?</A ></DT ><DT >7.24. <A HREF="setsockopt.html" >( SETSOCKOPT ) - I'm getting "ipfwadm: setsockopt failed: Protocol not available" when I try to use IPPORTFW!</A ></DT ><DT >7.25. <A HREF="samba.html" >( SAMBA ) - Microsoft File and Print Sharing and Microsoft Domain clients don't work through IP Masq!</A ></DT ><DT >7.26. <A HREF="ident.html" >( IDENT ) - IRC won't work properly for MASQed IRC users. Why?</A ></DT ><DT >7.27. <A HREF="irc-dcc.html" >( IRC DCC ) - mIRC doesn't work with DCC Sends</A ></DT ><DT >7.28. <A HREF="aliasing.html" >( IP Aliasing ) - Can IP Masquerade work with only ONE Ethernet network card?</A ></DT ><DT >7.29. <A HREF="multiple-lans.html" >( Multiple-LANs ) - I have two MASQed LANs but they cannot communicate with each other!</A ></DT ><DT >7.30. <A HREF="shaping.html" >( SHAPING ) - I want to be able to limit the speed of specific types of traffic</A ></DT ><DT >7.31. <A HREF="accounting.html" >( ACCOUNTING ) - I need to do accounting on who is using the network</A ></DT ><DT >7.32. <A HREF="multiple-ips.html" >( MULTIPLE IPs - DMZ segments) - I have several EXTERNAL IP addresses that I want to PORTFW to several internal machines. How do I do this?</A ></DT ><DT >7.33. <A HREF="one-to-one-nat.html" >( 1:1 NAT ) - I'd like to do 1:1 NAT but I can't figure out how to do it</A ></DT ><DT >7.34. <A HREF="netstat.html" >( Netstat ) - I'm trying to use the NETSTAT command to show my Masqueraded connections but its not working</A ></DT ><DT >7.35. <A HREF="vpns.html" >( VPNs ) - I would like to get Microsoft PPTP (GRE tunnels) and/or IPSEC (Linux SWAN) tunnels running through IP MASQ</A ></DT ><DT >7.36. <A HREF="games.html" >( Games ) - I want to get the XYZ network game to work through IP MASQ but it won't work. Help!</A ></DT ><DT >7.37. <A HREF="masq-stops-working.html" >( Stops working ) - IP MASQ works fine for a while but then it stops working. A reboot seems to fix this. Why?</A ></DT ><DT >7.38. <A HREF="smtp.html" >( SMTP Relay ) - Internal MASQed computers cannot send SMTP or POP-3 mail!</A ></DT ><DT >7.39. <A HREF="iproute2.html" >( Source Routing ) - I need different internal MASQed networks to exit on different external IP addresses</A ></DT ><DT >7.40. <A HREF="ipchains-on-2.4.x.html" >( IPCHAINS rulesets on 2.4.x kernels ) - What the ipchains.o module can do on 2.4.x kernels</A ></DT ><DT >7.41. <A HREF="iptables-vs-ipchains-vs-ipfwadm.html" >( IPTABLES vs. IPCHAINS vs. IPFWADM ) - Why do the 2.4.x, 2.2.x, and 2.0.x kernels use different firewall systems?</A ></DT ><DT >7.42. <A HREF="upgrades.html" >( Upgrades ) - I've just upgraded to the x.y.z kernel, why isn't IP Masquerade working?</A ></DT ><DT >7.43. <A HREF="eql.html" >( EQL ) - I need help with EQL connections and IP Masq</A ></DT ><DT >7.44. <A HREF="wussing-out.html" >( Wussing out ) - I can't get IP Masquerade to work! What options do I have for Windows Platforms?</A ></DT ><DT >7.45. <A HREF="developers.html" >( Developers ) - I want to help with IP Masquerade development. What can I do?</A ></DT ><DT >7.46. <A HREF="more-info.html" >( More INFO ) - Where can I find more information on IP Masquerade?</A ></DT ><DT >7.47. <A HREF="translators.html" >( Translators ) - I want to translate this HOWTO to another language, what should I do?</A ></DT ><DT >7.48. <A HREF="updates.html" >( Updates ) - This HOWTO seems out of date, are you still maintaining it? Can you include more information on ...? Are there any plans for making this better?</A ></DT ><DT >7.49. <A HREF="thanks.html" >( Thanks ) - I got IP Masquerade working, it's great! I want to thank you guys, what can I do?</A ></DT ></DL ></DIV ><P >If you can think of any useful FAQ suggestions, please send it to <A HREF="mailto:dranch@trinnet.net" TARGET="_top" >dranch@trinnet.net</A >. Please clearly state the question and an appropriate answer (if you have it). Thank you!</P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="looseudp.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="masq-supported-distributions.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Gamers: The LooseUDP patch</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" > </TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >( Distro ) - What Linux Distributions support IP Masquerading?</TD ></TR ></TABLE ></DIV ></BODY ></HTML >