Hello, masq GURUs!
First of all I'm sorry if my question and problem is well known. If it's
true, please, point me to decision docs.
And also sorry for my English ;)
My problem:
I've got an external net (DMZ) and an internal, hidden using
masquerading.
And I want to allow connections from external world to some (NNTP for
ex.) port of internal box.
Let AddrE - IP address of some external box, AddrL - linux running
masquerading, AddrM - internal (masqueraded) box.
AddrL have network cards in both (internal and external) networks.
I'm typing : ipautofw -A -r tcp 119 119 -h <AddrM>
Command runs OK and entry in /proc/net/ip_autofw appears.
After that I'm trying to access AddrM from AddrE
AddrE> telnet <AddrL> 119
But the connection times-out :( , because there is no ACKs for TCP
packets with SYN flag set.
Tcpdump on external interface says:
10:50:58.995297 AddrM.nntp > AddrE.25601: S 8734:8734(0) ack 2610645528
win 8760 <mss 1460> (DF)
10:51:00.975297 AddrE.25601 > AddrM.nntp: S 2610645527:2610645527(0) win
2144 <mss 1460>
10:51:00.975297 AddrM.nntp > AddrE.25601: . ack 1 win 8760 (DF)
10:51:01.935297 AddrM.nntp > AddrE.25601: S 8734:8734(0) ack 2610645528
win 8760 <mss 1460> (DF)
10:51:04.945297 AddrE.25601 > AddrM.nntp: S 2610645527:2610645527(0) win
2144 <mss 1460>
10:51:04.945297 AddrM.nntp > AddrE.25601: . ack 1 win 8760 (DF)
10:51:07.945297 AddrM.nntp > AddrE.25601: S 8734:8734(0) ack 2610645528
win 8760 <mss 1460> (DF)
10:51:12.885297 AddrE.25601 > AddrM.nntp: S 2610645527:2610645527(0) win
2144 <mss 1460>
10:51:12.885297 AddrM.nntp > AddrE.25601: . ack 1 win 8760 (DF)
10:51:19.965297 AddrM.nntp > AddrE.25601: S 8734:8734(0) ack 2610645528
win 8760 <mss 1460> (DF)
Tcpdump on internal interface says:
10:50:58.985297 AddrE.25601 > AddrM.nntp: S 2610645527:2610645527(0) win
2144 <mss 1460>
10:51:00.975297 AddrE.25601 > AddrM.nntp: S 2610645527:2610645527(0) win
2144 <mss 1460>
10:51:04.945297 AddrE.25601 > AddrM.nntp: S 2610645527:2610645527(0) win
2144 <mss 1460>
10:51:12.885297 AddrE.25601 > AddrM.nntp: S 2610645527:2610645527(0) win
2144 <mss 1460>
Independent sniffer from internal net gives the same results.
I don't understand anything
Perhaps, tcpdump on external interface gives me wrong results, but I've
no other opportunity to run sniffer on my external network :(
Can anybody tell me were I'm wrong? May be I messed something?
I'm running RH 5.1 with kernel 2.0.35 and ipautofw-2.0.0.
Additional question:
I know about TCPDeath problem caused by ipautofw. How to solve it? Is
were any patch?
Thanks for any help.
=============================================
Regards, Alexey Sobolev.
St. Petersburg, Russia.
ICQ: 170-140-26
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