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[saraf]

Greetings,

My DSL-2750U has been compromised and it now blocks all outbound access to port 22. (I have confirmed with my ISP - and they are not blocking the port from their side)

I hope that upgrading the firmware to the latest version might solve this problem.

The link for downloading the latest firmware on the D-Link India support site is ftp://support.dlink.co.in/firmware/DSL/DSL-2750UV1/DSL-2750UV1.zip
(Can be found on http://www.dlink.co.in/products/?pid=DSL-2750u and then clicking on Support->Firmware)
This requires authentication - and the user name and password combination for getting this file cannot be found -anywhere- even after googling.
I would be grateful if you can tell me how I may get this file.

Another question:
Does pressing the hardware 'reset' pin button on the bottom side of the DSL-2750U unit actually restore the entire firmware image to that of the Factory Default (thereby enabling me to be rid of the malware compromised image), or does it merely reset the setting values to default?

Thanks!
warm regards,
Saraf

[GreenBay42]

I will see if I can get the file. There should not be a login for customers to download firmware.

The reset button only resets all the setting back to the default value. It does not "reflash" the firmware.

What hardware version is your unit? U1 or V1?

[GreenBay42]

The latest version I see is 1.02 for version U1. 1.07 is for V1.  There was a version IN 1.10 but that was released in 2011.

Go to http://tsd.dlink.com.tw. Select DSL-2750U from the drop-downs. The 1.02 IN is the 3rd one down in the list and the 1.07 is right below that.

[saraf]

Thanks for your prompt response!
The hardware version of my 2750U is A1

[saraf]

There is a link on the taiwan page http://tsd.dlink.com.tw/downloads2008detail.asp for Manual v1.00: DSL-2750U A1 (for IN) and QIG v2.00(IN): DSL-2750U A1 (for IN)
But, there is no firmware for A1.

[GreenBay42]

Unfortunately my database goes back to 2008 and I do not see any firmware for revision A.

I know earlier releases used ISP-specific firmware supplied by the ISP. Unfortunately if there is nothing posted at tsd.dlink.com.tw there may not be a general firmware release. The only thing you can do is contact tech support and see if they have a public firmware for revision A.

[GreenBay42]

Getting back to the main issue, if after a reset is port 22 still blocked? What are you doing to test if the outbound port is blocked?

Can you log in to the web UI?

[saraf]

Yes, after a reset the port is still blocked.
I am just trying to ssh to my servers on the internet - and that process times out.
(tried this from multiple devices connected to the 2750U to rule out OS Firewall issues)

If I use a different gateway device - say my 4G WiFi mobile hotspot, from the same client ssh devices, it works.

Yes ... I can log in to the web UI.

[saraf]

I had an older DSL-2750U with hardware version C1 and firmware version
Software Version:    IN_1.10
Bootloader (CFE) Version:    1.0.37-106.5
DSL PHY and Driver Version:   A2pD033c.d23h
Wireless Driver Version:    5.60.120.3.cpe4.406.0

This one is clean. And port 22 is still not accessible.
So the malware issue can be ruled out.

(although that issue still puzzles me ... why did ISP page of Cote d'Ivoire
https://www.google.co.in/search?client=firefox-b&q=MOOV+portail&oq=MOOV+portail
come up when I tried to access the configuration page of ADSL router.... issue is not reproducible.)

I have talked with Support on Chat and got a firmware image 1.01 from them over email.
After flashing the new image received from them - the port 22 block still persists.

About the ssh port 22 outbound access not usable, how can this issue be debugged?