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by **Basher52** » Fri Jan 16, 2009 1:56 pm

The new server I'm installing is for my sister and her husband and during the test I locked all IP addresses out of it but I sometimes want her to take a look at it. The bad thing is that she's on ADSL and that IP address' lease is like only an hour or so and the next time she turns the PC on, she got a new IP and can't get in.
Is there something that I can use to ease this pain. When her IP changes she won't call me/email me or anything to say that, she just gives up.
I need an application that can let her in whatever her IP is as long as she uses "her client" of this to open her IP in the firewall.
In this case it's for web, but it could be for, like anything.

If you know what I'm talking about?

by **Void Main** » Fri Jan 16, 2009 2:20 pm

I use "knockd" on my firewall to give temporary access to specified ports from whatever IP address I might be on. You add something to her machine's startup or browser startup that would send the appropriate knock sequence to her server and give her dynamic address access.

http://www.zeroflux.org/cgi-bin/cvstrac.cgi/knock/wiki

by **Basher52** » Fri Jan 16, 2009 3:56 pm

now when you say it I remember that you said this before
*shame on me for not remembering, sorry*

by **Basher52** » Wed Jan 21, 2009 2:19 am

This don't seem to suite my machine and I can't find any prerequisites either on that site.

Code: Select all: [root@ftp knock-0.5]# ./config config.guess config.sub configure [root@ftp knock-0.5]# ./configure checking for gcc... gcc checking for C compiler default output file name... a.out checking whether the C compiler works... yes checking whether we are cross compiling... no checking for suffix of executables... checking for suffix of object files... o checking whether we are using the GNU C compiler... yes checking whether gcc accepts -g... yes checking for gcc option to accept ANSI C... none needed checking for g++... g++ checking whether we are using the GNU C++ compiler... yes checking whether g++ accepts -g... yes checking for a BSD-compatible install... /usr/bin/install -c checking for pcap_open_live in -lpcap... no checking how to run the C preprocessor... gcc -E checking for egrep... grep -E checking for ANSI C header files... yes checking for sys/wait.h that is POSIX.1 compatible... yes checking for sys/types.h... yes checking for sys/stat.h... yes checking for stdlib.h... yes checking for string.h... yes checking for memory.h... yes checking for strings.h... yes checking for inttypes.h... yes checking for stdint.h... yes checking for unistd.h... yes checking arpa/inet.h usability... yes checking arpa/inet.h presence... yes checking for arpa/inet.h... yes checking pcap.h usability... no checking pcap.h presence... no checking for pcap.h... no checking netdb.h usability... yes checking netdb.h presence... yes checking for netdb.h... yes checking netinet/in.h usability... yes checking netinet/in.h presence... yes checking for netinet/in.h... yes checking for stdlib.h... (cached) yes checking for string.h... (cached) yes checking sys/socket.h usability... yes checking sys/socket.h presence... yes checking for sys/socket.h... yes checking syslog.h usability... yes checking syslog.h presence... yes checking for syslog.h... yes checking for unistd.h... (cached) yes checking for an ANSI C-conforming const... yes checking for size_t... yes checking whether struct tm is in sys/time.h or time.h... time.h checking for pid_t... yes checking for unistd.h... (cached) yes checking vfork.h usability... no checking vfork.h presence... no checking for vfork.h... no checking for fork... yes checking for vfork... yes checking for working fork... yes checking for working vfork... (cached) yes checking for stdlib.h... (cached) yes checking for GNU libc compatible malloc... yes checking return type of signal handlers... void checking for vprintf... yes checking for _doprnt... no checking for inet_ntoa... yes checking for memmove... yes checking for strcasecmp... yes checking for strdup... yes checking for strstr... yes configure: creating ./config.status config.status: creating Makefile config.status: creating config.h [root@ftp knock-0.5]#

Code: Select all: [root@ftp knock-0.5]# make gcc -g -O2 -g -Wall -pedantic -fno-exceptions -D_GNU_SOURCE -I. -o src/knockd.o -c src/knockd.c src/knockd.c:47:18: error: pcap.h: No such file or directory src/knockd.c:121: warning: 'struct pcap_pkthdr' declared inside parameter list src/knockd.c:121: warning: its scope is only this definition or declaration, which is probably not what you want src/knockd.c:123: error: expected '=', ',', ';', 'asm' or '__attribute__' before '*' token src/knockd.c:134: error: 'PATH_MAX' undeclared here (not in a function) src/knockd.c: In function 'main': src/knockd.c:140: error: 'PCAP_ERRBUF_SIZE' undeclared (first use in this function) src/knockd.c:140: error: (Each undeclared identifier is reported only once src/knockd.c:140: error: for each function it appears in.) src/knockd.c:196: error: 'cap' undeclared (first use in this function) src/knockd.c:196: warning: implicit declaration of function 'pcap_open_live' src/knockd.c:204: warning: implicit declaration of function 'pcap_datalink' src/knockd.c:206: error: 'DLT_EN10MB' undeclared (first use in this function) src/knockd.c:209: error: 'DLT_LINUX_SLL' undeclared (first use in this function) src/knockd.c:212: error: 'DLT_RAW' undeclared (first use in this function) src/knockd.c:256: warning: implicit declaration of function 'pcap_dispatch' src/knockd.c:259: warning: implicit declaration of function 'pcap_perror' src/knockd.c:140: warning: unused variable 'pcapErr' src/knockd.c: In function 'cleanup': src/knockd.c:346: warning: implicit declaration of function 'pcap_close' src/knockd.c:346: error: 'cap' undeclared (first use in this function) src/knockd.c: In function 'parseconfig': src/knockd.c:438: warning: unused variable 'line' src/knockd.c: In function 'get_next_one_time_sequence': src/knockd.c:695: warning: unused variable 'line' src/knockd.c: In function 'generate_pcap_filter': src/knockd.c:783: error: storage size of 'bpf_prog' isn't known src/knockd.c:972: warning: implicit declaration of function 'pcap_compile' src/knockd.c:972: error: 'cap' undeclared (first use in this function) src/knockd.c:976: warning: implicit declaration of function 'pcap_setfilter' src/knockd.c:980: warning: implicit declaration of function 'pcap_freecode' src/knockd.c:783: warning: unused variable 'bpf_prog' src/knockd.c: At top level: src/knockd.c:1161: warning: 'struct pcap_pkthdr' declared inside parameter list src/knockd.c:1161: error: conflicting types for 'sniff' src/knockd.c:121: error: previous declaration of 'sniff' was here src/knockd.c: In function 'sniff': src/knockd.c:1174: error: dereferencing pointer to incomplete type src/knockd.c:1181: error: 'DLT_EN10MB' undeclared (first use in this function) src/knockd.c:1187: error: 'DLT_LINUX_SLL' undeclared (first use in this function) src/knockd.c:1189: error: 'DLT_RAW' undeclared (first use in this function) src/knockd.c:1245: error: dereferencing pointer to incomplete type src/knockd.c:1386: warning: unused variable 'parsed_stop_cmd' src/knockd.c:1385: warning: unused variable 'parsed_start_cmd' make: *** [src/knockd.o] Error 1 [root@ftp knock-0.5]#

by **Void Main** » Wed Jan 21, 2009 9:02 am

Looks like you need to install your pcap headers:

# yum install libpcap-devel

P.S. I actually had built an RPM of knock back in December '05 (FC4). The binary RPM might work directly but surely (maybe) you could rebuild the SRC RPM and it should work.

http://voidmain.is-a-geek.net/files/RPMS/knock/

by **Basher52** » Wed Jan 21, 2009 9:15 am

Nope still something missing or some other stuff

Code: Select all: [root@ftp knock-0.5]# make gcc -g -O2 -g -Wall -pedantic -fno-exceptions -D_GNU_SOURCE -I. -o src/knockd.o -c src/knockd.c src/knockd.c:134: error: 'PATH_MAX' undeclared here (not in a function) src/knockd.c: In function 'parseconfig': src/knockd.c:438: warning: unused variable 'line' src/knockd.c: In function 'get_next_one_time_sequence': src/knockd.c:695: warning: unused variable 'line' src/knockd.c: In function 'sniff': src/knockd.c:1386: warning: unused variable 'parsed_stop_cmd' src/knockd.c:1385: warning: unused variable 'parsed_start_cmd' make: *** [src/knockd.o] Error 1

by **Void Main** » Wed Jan 21, 2009 10:34 am

I see there is a newer SRC RPM:
http://www.invoca.ch/pub/packages/knock/

I get the same error you get. I am sure it will be an easy fix but I do not have time right now. I'll try and get to it when I get home from work and fix the source.

by **Basher52** » Wed Jan 21, 2009 11:48 am

no worries mate

by **Void Main** » Wed Jan 21, 2009 5:07 pm

A quick fix would be to add this line to "src/knockd.c" right under all the other include files near the top:

Code: Select all: #include <linux/limits.h>

by **Basher52** » Wed Jan 21, 2009 5:15 pm

You sure know your stuff

I'll make install this tomorrow and start to config it

thx again man

by **Basher52** » Thu Jan 22, 2009 5:47 am

yep it works
but from work using this win32 knock client don't seem to work properly.
sometimes it knocks with the same port twice thus I have to knock a couple of times to get the sequence right, but forgetting this it's working

by **Void Main** » Thu Jan 22, 2009 9:27 am

Basher52 wrote:yep it works
but from work using this win32 knock client don't seem to work properly.
sometimes it knocks with the same port twice thus I have to knock a couple of times to get the sequence right, but forgetting this it's working :)

Hmm, that's odd. In my case I can't do the knock sequence from work at all because of outbound firewall restrictions. No problem though as for work addresses I just allow them directly to specified resources in my firewall configuration since they are known non-malicious static IP addresses. So really the only time I do the knock is if I am traveling.

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Some app to handle different IP address thru the FW

Some app to handle different IP address thru the FW

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