[Openswan Users] Forcing port 4500

Swartz, Patrick H Patrick.Swartz at firstdata.com
Sat Feb 12 15:32:55 EST 2011

Thanks for the quick reply !!  

Well, adding that to the ipsec.conf file did the trick so far as setting the outgoing port to 4500.  However, it didn't work as I expected.
I set that on both sides, but after restarting and sending a test ping I see this in both secure logs --

[Left log]
Feb 12 01:13:05 r9tvmp502 pluto[20492]: | handling event EVENT_RETRANSMIT for <invalid> "r9tvmp502-jerry" #1
Feb 12 01:13:05 r9tvmp502 pluto[20492]: | sending 592 bytes for EVENT_RETRANSMIT through eth0:4500 to (using #1)

[Right log]
Feb 12 14:20:59 rhel5-3atest pluto[25332]: "r9tvmp502-jerry" #2: initiating Main Mode to replace #1
Feb 12 14:20:59 rhel5-3atest pluto[25332]: | sending 592 bytes for main_outI1 through eth0:4500 to (using #2)

The brass-tax of this is I just need to work around our firewalls that are blocking port 500.

Here is a diagram of the test environment --
[left side] r9tvmp502( --> jerry( [right side]

Here is the main ipsec.conf that is the same on both sides --
version 2.0     # conforms to second version of ipsec.conf specification

# basic configuration
config setup
        # Debug-logging controls:  "none" for (almost) none, "all" for lots.
        # klipsdebug=none
        plutodebug="control parsing"
        plutoopts="--ikeport 4500"
        # For Red Hat Enterprise Linux and Fedora, leave protostack=netkey
        # Enable this if you see "failed to find any available worker"

And the conn
conn r9tvmp502-jerry

Patrick Swartz
UNIX Planning & Engineering (DSUSSE)
First Data 
402-777-7337 desk
402-201-1192 Company cell
402-871-8981 Personal cell

-----Original Message-----
From: Paul Wouters [mailto:paul at xelerance.com] 
Sent: Saturday, February 12, 2011 12:10 PM
To: Swartz, Patrick H
Cc: users at openswan.org
Subject: Re: [Openswan Users] Forcing port 4500

On Sat, 12 Feb 2011, Swartz, Patrick H wrote:

> After much trial-and-error, I think I have found the culprit – we have firewalls that are blocking port 500.  However, port 4500 is open.
> So my questions is – Can I force openswan to use port 4500 for everything?
> I have set  --“ forceencaps=yes ” – in the conn section of the openswan.conf file and “ nat_traversal=yes ” even though I’m not using
> NAT’ing just yet.
> However, after watching the /var/log/secure it looks like packets are still being sent out on port 500.

The first packet still goes out over port 500.

You can try adding this to config setup in ipsec.conf:

 	plutoopts="--ikeport 4500"

You might need to pick something other then 4500 to not interfere with the "jumping to 4500" though.

Let us know how this goes,


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