On Fri, Nov 07, 2025 at 10:15:20PM +0000, Jeremy Harris via Exim-users wrote:
> On 2025/11/07 8:54 PM, Marc MERLIN via Exim-users wrote:
> > Logs showing when things work, below.  Any idea how I can capture this 
> > better or what could be
> > going wrong?
> 
> Actually, that had its own problem:
 
I understand it failed, but it was working as intended, it was spam, the
server on the other side wasn't taking connections, it causes
callout/callback to fail, and the spam score to go up. All good.

> So, at first sight it's not your problem but theirs.

Correct. But this is not cause for a panic log of "Cannot assign
requested address"

> Going back to the recipient verify defer - Cannot assign requested address...
> that would be a problem on your system.  It it heavily loaded?  My first

that's my understanding too, but I can't find why or what. It's not very
loaded, it's not a super busy mail server, it has 32000 ports to call
out on and nowhere close to using them.

> thought would be the assignment of the local port along with the IP being
> used for the outbound interface, and the bind syscall failing due to
> ephemeral port exhaustion.   Any system-wide settings reserving ports
> could be reducing the pool available, too (I used to see extreme examples
> of that in a previous $JOB, associated with some major software packages...).

Some settings google recommended to check:
magic:~# cat /proc/sys/net/ipv4/ip_local_port_range
32768   60999
magic:# sysctl -p
net.ipv4.tcp_tw_reuse = 1
magic:# cat /proc/sys/net/netfilter/nf_conntrack_count
1321
magic:# cat /proc/sys/net/netfilter/nf_conntrack_max
262144

> How to get more info?   Well, there's the ACL-driven speculative debug 
> facility.
> Start debug (to file) early on in the life of a message-handling, and then
> discard it later if all has gone well past the roughly-determined danger 
> point.

Oh, I didn't know about that option, will try it out if I can't figure
out why/when it's failing.

Thanks,
Marc
-- 
"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
 
Home page: http://marc.merlins.org/  

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